diff --git a/scripts/build_spec.py b/scripts/build_spec.py
index c38d0bd65..cca5a1bf9 100644
--- a/scripts/build_spec.py
+++ b/scripts/build_spec.py
@@ -82,7 +82,7 @@ def get_eth1_data(distance: uint64) -> Bytes32:
     return hash(distance)
 
 
-def hash(x: bytes) -> Bytes32:
+def hash(x: bytes) -> Bytes32:  # type: ignore
     if x not in hash_cache:
         hash_cache[x] = Bytes32(_hash(x))
     return hash_cache[x]
diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md
index 1c4a4eae9..22522b3bd 100644
--- a/specs/core/0_beacon-chain.md
+++ b/specs/core/0_beacon-chain.md
@@ -593,6 +593,34 @@ def is_active_validator(validator: Validator, epoch: Epoch) -> bool:
     return validator.activation_epoch <= epoch < validator.exit_epoch
 ```
 
+#### `is_eligible_for_activation_queue`
+
+```python
+def is_eligible_for_activation_queue(validator: Validator) -> bool:
+    """
+    Check if ``validator`` is eligible to be placed into the activation queue.
+    """
+    return (
+        validator.activation_eligibility_epoch == FAR_FUTURE_EPOCH
+        and validator.effective_balance == MAX_EFFECTIVE_BALANCE
+    )
+```
+
+#### `is_eligible_for_activation`
+
+```python
+def is_eligible_for_activation(state: BeaconState, validator: Validator) -> bool:
+    """
+    Check if ``validator`` is eligible for activation.
+    """
+    return (
+        # Placement in queue is finalized
+        validator.activation_eligibility_epoch <= state.finalized_checkpoint.epoch
+        # Has not yet been activated
+        and validator.activation_epoch == FAR_FUTURE_EPOCH
+    )
+```
+
 #### `is_slashable_validator`
 
 ```python
@@ -630,8 +658,8 @@ def is_valid_indexed_attestation(state: BeaconState, indexed_attestation: Indexe
     # Verify max number of indices
     if not len(indices) <= MAX_VALIDATORS_PER_COMMITTEE:
         return False
-    # Verify indices are sorted
-    if not indices == sorted(indices):
+    # Verify indices are sorted and unique
+    if not indices == sorted(set(indices)):
         return False
     # Verify aggregate signature
     if not bls_verify(
@@ -1304,26 +1332,22 @@ def process_rewards_and_penalties(state: BeaconState) -> None:
 def process_registry_updates(state: BeaconState) -> None:
     # Process activation eligibility and ejections
     for index, validator in enumerate(state.validators):
-        if (
-            validator.activation_eligibility_epoch == FAR_FUTURE_EPOCH
-            and validator.effective_balance == MAX_EFFECTIVE_BALANCE
-        ):
-            validator.activation_eligibility_epoch = get_current_epoch(state)
+        if is_eligible_for_activation_queue(validator):
+            validator.activation_eligibility_epoch = get_current_epoch(state) + 1
 
         if is_active_validator(validator, get_current_epoch(state)) and validator.effective_balance <= EJECTION_BALANCE:
             initiate_validator_exit(state, ValidatorIndex(index))
 
-    # Queue validators eligible for activation and not dequeued for activation prior to finalized epoch
+    # Queue validators eligible for activation and not yet dequeued for activation
     activation_queue = sorted([
         index for index, validator in enumerate(state.validators)
-        if validator.activation_eligibility_epoch != FAR_FUTURE_EPOCH
-        and validator.activation_epoch >= compute_activation_exit_epoch(state.finalized_checkpoint.epoch)
-    ], key=lambda index: state.validators[index].activation_eligibility_epoch)
-    # Dequeued validators for activation up to churn limit (without resetting activation epoch)
+        if is_eligible_for_activation(state, validator)
+        # Order by the sequence of activation_eligibility_epoch setting and then index
+    ], key=lambda index: (state.validators[index].activation_eligibility_epoch, index))
+    # Dequeued validators for activation up to churn limit
     for index in activation_queue[:get_validator_churn_limit(state)]:
         validator = state.validators[index]
-        if validator.activation_epoch == FAR_FUTURE_EPOCH:
-            validator.activation_epoch = compute_activation_exit_epoch(get_current_epoch(state))
+        validator.activation_epoch = compute_activation_exit_epoch(get_current_epoch(state))
 ```
 
 #### Slashings
@@ -1484,6 +1508,7 @@ def process_attestation(state: BeaconState, attestation: Attestation) -> None:
     data = attestation.data
     assert data.index < get_committee_count_at_slot(state, data.slot)
     assert data.target.epoch in (get_previous_epoch(state), get_current_epoch(state))
+    assert data.target.epoch == compute_epoch_at_slot(data.slot)
     assert data.slot + MIN_ATTESTATION_INCLUSION_DELAY <= state.slot <= data.slot + SLOTS_PER_EPOCH
 
     committee = get_beacon_committee(state, data.slot, data.index)
diff --git a/specs/core/0_fork-choice.md b/specs/core/0_fork-choice.md
index ae150de00..2191c24a2 100644
--- a/specs/core/0_fork-choice.md
+++ b/specs/core/0_fork-choice.md
@@ -104,11 +104,18 @@ def get_genesis_store(genesis_state: BeaconState) -> Store:
     )
 ```
 
+#### `get_slots_since_genesis`
+
+```python
+def get_slots_since_genesis(store: Store) -> int:
+    return (store.time - store.genesis_time) // SECONDS_PER_SLOT
+```
+
 #### `get_current_slot`
 
 ```python
 def get_current_slot(store: Store) -> Slot:
-    return Slot((store.time - store.genesis_time) // SECONDS_PER_SLOT)
+    return Slot(GENESIS_SLOT + get_slots_since_genesis(store))
 ```
 
 #### `compute_slots_since_epoch_start`
@@ -272,7 +279,7 @@ def on_block(store: Store, signed_block: SignedBeaconBlock) -> None:
     assert block.parent_root in store.block_states
     pre_state = store.block_states[block.parent_root].copy()
     # Blocks cannot be in the future. If they are, their consideration must be delayed until the are in the past.
-    assert store.time >= pre_state.genesis_time + block.slot * SECONDS_PER_SLOT
+    assert get_current_slot(store) >= block.slot
     # Add new block to the store
     store.blocks[hash_tree_root(block)] = block
     # Check block is a descendant of the finalized block
@@ -289,7 +296,8 @@ def on_block(store: Store, signed_block: SignedBeaconBlock) -> None:
 
     # Update justified checkpoint
     if state.current_justified_checkpoint.epoch > store.justified_checkpoint.epoch:
-        store.best_justified_checkpoint = state.current_justified_checkpoint
+        if state.current_justified_checkpoint.epoch > store.best_justified_checkpoint.epoch:
+            store.best_justified_checkpoint = state.current_justified_checkpoint
         if should_update_justified_checkpoint(store, state.current_justified_checkpoint):
             store.justified_checkpoint = state.current_justified_checkpoint
 
@@ -315,12 +323,13 @@ def on_attestation(store: Store, attestation: Attestation) -> None:
     # Use GENESIS_EPOCH for previous when genesis to avoid underflow
     previous_epoch = current_epoch - 1 if current_epoch > GENESIS_EPOCH else GENESIS_EPOCH
     assert target.epoch in [current_epoch, previous_epoch]
+    assert target.epoch == compute_epoch_at_slot(attestation.data.slot)
 
     # Attestations target be for a known block. If target block is unknown, delay consideration until the block is found
     assert target.root in store.blocks
     # Attestations cannot be from future epochs. If they are, delay consideration until the epoch arrives
     base_state = store.block_states[target.root].copy()
-    assert store.time >= base_state.genesis_time + compute_start_slot_at_epoch(target.epoch) * SECONDS_PER_SLOT
+    assert get_current_slot(store) >= compute_start_slot_at_epoch(target.epoch)
 
     # Attestations must be for a known block. If block is unknown, delay consideration until the block is found
     assert attestation.data.beacon_block_root in store.blocks
@@ -335,7 +344,7 @@ def on_attestation(store: Store, attestation: Attestation) -> None:
 
     # Attestations can only affect the fork choice of subsequent slots.
     # Delay consideration in the fork choice until their slot is in the past.
-    assert store.time >= (attestation.data.slot + 1) * SECONDS_PER_SLOT
+    assert get_current_slot(store) >= attestation.data.slot + 1
 
     # Get state at the `target` to validate attestation and calculate the committees
     indexed_attestation = get_indexed_attestation(target_state, attestation)
diff --git a/test_libs/pyspec/eth2spec/test/fork_choice/test_on_attestation.py b/test_libs/pyspec/eth2spec/test/fork_choice/test_on_attestation.py
index 8f1d6f74f..d7fbc4777 100644
--- a/test_libs/pyspec/eth2spec/test/fork_choice/test_on_attestation.py
+++ b/test_libs/pyspec/eth2spec/test/fork_choice/test_on_attestation.py
@@ -84,6 +84,29 @@ def test_on_attestation_past_epoch(spec, state):
     run_on_attestation(spec, state, store, attestation, False)
 
 
+@with_all_phases
+@spec_state_test
+def test_on_attestation_mismatched_target_and_slot(spec, state):
+    store = spec.get_genesis_store(state)
+    spec.on_tick(store, store.time + spec.SECONDS_PER_SLOT * spec.SLOTS_PER_EPOCH)
+
+    block = build_empty_block_for_next_slot(spec, state)
+    signed_block = state_transition_and_sign_block(spec, state, block)
+
+    # store block in store
+    spec.on_block(store, signed_block)
+
+    attestation = get_valid_attestation(spec, state, slot=block.slot)
+    attestation.data.target.epoch += 1
+    sign_attestation(spec, state, attestation)
+
+    assert attestation.data.target.epoch == spec.GENESIS_EPOCH + 1
+    assert spec.compute_epoch_at_slot(attestation.data.slot) == spec.GENESIS_EPOCH
+    assert spec.compute_epoch_at_slot(spec.get_current_slot(store)) == spec.GENESIS_EPOCH + 1
+
+    run_on_attestation(spec, state, store, attestation, False)
+
+
 @with_all_phases
 @spec_state_test
 def test_on_attestation_target_not_in_store(spec, state):
diff --git a/test_libs/pyspec/eth2spec/test/fork_choice/test_on_block.py b/test_libs/pyspec/eth2spec/test/fork_choice/test_on_block.py
index 4fda49664..10d1c0011 100644
--- a/test_libs/pyspec/eth2spec/test/fork_choice/test_on_block.py
+++ b/test_libs/pyspec/eth2spec/test/fork_choice/test_on_block.py
@@ -168,7 +168,7 @@ def test_on_block_update_justified_checkpoint_within_safe_slots(spec, state):
 
 @with_all_phases
 @spec_state_test
-def test_on_block_outside_safe_slots_and_old_block(spec, state):
+def test_on_block_outside_safe_slots_and_multiple_better_justified(spec, state):
     # Initialization
     store = spec.get_genesis_store(state)
     time = 100
@@ -187,20 +187,30 @@ def test_on_block_outside_safe_slots_and_old_block(spec, state):
     just_block.slot = spec.compute_start_slot_at_epoch(store.justified_checkpoint.epoch)
     store.blocks[just_block.hash_tree_root()] = just_block
 
-    # Mock the justified checkpoint
-    just_state = store.block_states[last_block_root]
-    new_justified = spec.Checkpoint(
-        epoch=just_state.current_justified_checkpoint.epoch + 1,
-        root=just_block.hash_tree_root(),
-    )
-    just_state.current_justified_checkpoint = new_justified
-
-    block = build_empty_block_for_next_slot(spec, just_state)
-    signed_block = state_transition_and_sign_block(spec, deepcopy(just_state), block)
-
+    # Step time past safe slots
     spec.on_tick(store, store.time + spec.SAFE_SLOTS_TO_UPDATE_JUSTIFIED * spec.SECONDS_PER_SLOT)
     assert spec.get_current_slot(store) % spec.SLOTS_PER_EPOCH >= spec.SAFE_SLOTS_TO_UPDATE_JUSTIFIED
-    run_on_block(spec, store, signed_block)
 
-    assert store.justified_checkpoint != new_justified
-    assert store.best_justified_checkpoint == new_justified
+    previously_justified = store.justified_checkpoint
+
+    # Add a series of new blocks with "better" justifications
+    best_justified_checkpoint = spec.Checkpoint(epoch=0)
+    for i in range(3, 0, -1):
+        just_state = store.block_states[last_block_root]
+        new_justified = spec.Checkpoint(
+            epoch=previously_justified.epoch + i,
+            root=just_block.hash_tree_root(),
+        )
+        if new_justified.epoch > best_justified_checkpoint.epoch:
+            best_justified_checkpoint = new_justified
+
+        just_state.current_justified_checkpoint = new_justified
+
+        block = build_empty_block_for_next_slot(spec, just_state)
+        signed_block = state_transition_and_sign_block(spec, deepcopy(just_state), block)
+
+        run_on_block(spec, store, signed_block)
+
+    assert store.justified_checkpoint == previously_justified
+    # ensure the best from the series was stored
+    assert store.best_justified_checkpoint == best_justified_checkpoint
diff --git a/test_libs/pyspec/eth2spec/test/phase_0/block_processing/test_process_attestation.py b/test_libs/pyspec/eth2spec/test/phase_0/block_processing/test_process_attestation.py
index f19bc66d3..d48386fd4 100644
--- a/test_libs/pyspec/eth2spec/test/phase_0/block_processing/test_process_attestation.py
+++ b/test_libs/pyspec/eth2spec/test/phase_0/block_processing/test_process_attestation.py
@@ -177,6 +177,20 @@ def test_invalid_index(spec, state):
     yield from run_attestation_processing(spec, state, attestation, False)
 
 
+@with_all_phases
+@spec_state_test
+def test_mismatched_target_and_slot(spec, state):
+    next_epoch(spec, state)
+    next_epoch(spec, state)
+
+    attestation = get_valid_attestation(spec, state)
+    attestation.data.slot = attestation.data.slot - spec.SLOTS_PER_EPOCH
+
+    sign_attestation(spec, state, attestation)
+
+    yield from run_attestation_processing(spec, state, attestation, False)
+
+
 @with_all_phases
 @spec_state_test
 def test_old_target_epoch(spec, state):
diff --git a/test_libs/pyspec/eth2spec/test/phase_0/block_processing/test_process_attester_slashing.py b/test_libs/pyspec/eth2spec/test/phase_0/block_processing/test_process_attester_slashing.py
index 85e807ec0..98a6e25e5 100644
--- a/test_libs/pyspec/eth2spec/test/phase_0/block_processing/test_process_attester_slashing.py
+++ b/test_libs/pyspec/eth2spec/test/phase_0/block_processing/test_process_attester_slashing.py
@@ -252,6 +252,76 @@ def test_att2_bad_replaced_index(spec, state):
     yield from run_attester_slashing_processing(spec, state, attester_slashing, False)
 
 
+@with_all_phases
+@spec_state_test
+@always_bls
+def test_att1_duplicate_index_normal_signed(spec, state):
+    attester_slashing = get_valid_attester_slashing(spec, state, signed_1=False, signed_2=True)
+
+    indices = attester_slashing.attestation_1.attesting_indices
+    indices.pop(1)  # remove an index, make room for the additional duplicate index.
+    attester_slashing.attestation_1.attesting_indices = sorted(indices)
+
+    # sign it, the signature will be valid for a single occurence. If the transition accidentally ignores the duplicate.
+    sign_indexed_attestation(spec, state, attester_slashing.attestation_1)
+
+    indices.append(indices[0])  # add one of the indices a second time
+    attester_slashing.attestation_1.attesting_indices = sorted(indices)
+
+    # it will just appear normal, unless the double index is spotted
+    yield from run_attester_slashing_processing(spec, state, attester_slashing, False)
+
+
+@with_all_phases
+@spec_state_test
+@always_bls
+def test_att2_duplicate_index_normal_signed(spec, state):
+    attester_slashing = get_valid_attester_slashing(spec, state, signed_1=True, signed_2=False)
+
+    indices = attester_slashing.attestation_2.attesting_indices
+    indices.pop(2)  # remove an index, make room for the additional duplicate index.
+    attester_slashing.attestation_2.attesting_indices = sorted(indices)
+
+    # sign it, the signature will be valid for a single occurence. If the transition accidentally ignores the duplicate.
+    sign_indexed_attestation(spec, state, attester_slashing.attestation_2)
+
+    indices.append(indices[1])  # add one of the indices a second time
+    attester_slashing.attestation_2.attesting_indices = sorted(indices)
+
+    # it will just appear normal, unless the double index is spotted
+    yield from run_attester_slashing_processing(spec, state, attester_slashing, False)
+
+
+@with_all_phases
+@spec_state_test
+@always_bls
+def test_att1_duplicate_index_double_signed(spec, state):
+    attester_slashing = get_valid_attester_slashing(spec, state, signed_1=False, signed_2=True)
+
+    indices = attester_slashing.attestation_1.attesting_indices
+    indices.pop(1)  # remove an index, make room for the additional duplicate index.
+    indices.append(indices[2])  # add one of the indices a second time
+    attester_slashing.attestation_1.attesting_indices = sorted(indices)
+    sign_indexed_attestation(spec, state, attester_slashing.attestation_1)  # will have one attester signing it double
+
+    yield from run_attester_slashing_processing(spec, state, attester_slashing, False)
+
+
+@with_all_phases
+@spec_state_test
+@always_bls
+def test_att2_duplicate_index_double_signed(spec, state):
+    attester_slashing = get_valid_attester_slashing(spec, state, signed_1=True, signed_2=False)
+
+    indices = attester_slashing.attestation_2.attesting_indices
+    indices.pop(1)  # remove an index, make room for the additional duplicate index.
+    indices.append(indices[2])  # add one of the indices a second time
+    attester_slashing.attestation_2.attesting_indices = sorted(indices)
+    sign_indexed_attestation(spec, state, attester_slashing.attestation_2)  # will have one attester signing it double
+
+    yield from run_attester_slashing_processing(spec, state, attester_slashing, False)
+
+
 @with_all_phases
 @spec_state_test
 def test_unsorted_att_1(spec, state):
diff --git a/test_libs/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_registry_updates.py b/test_libs/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_registry_updates.py
index bfd992ffa..526aba277 100644
--- a/test_libs/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_registry_updates.py
+++ b/test_libs/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_registry_updates.py
@@ -17,24 +17,80 @@ def mock_deposit(spec, state, index):
 
 @with_all_phases
 @spec_state_test
-def test_activation(spec, state):
+def test_add_to_activation_queue(spec, state):
+    # move past first two irregular epochs wrt finality
+    next_epoch(spec, state)
+    next_epoch(spec, state)
+
     index = 0
     mock_deposit(spec, state, index)
 
-    for _ in range(spec.MAX_SEED_LOOKAHEAD + 1):
-        next_epoch(spec, state)
+    yield from run_process_registry_updates(spec, state)
+
+    # validator moved into queue
+    assert state.validators[index].activation_eligibility_epoch != spec.FAR_FUTURE_EPOCH
+    assert state.validators[index].activation_epoch == spec.FAR_FUTURE_EPOCH
+    assert not spec.is_active_validator(state.validators[index], spec.get_current_epoch(state))
+
+
+@with_all_phases
+@spec_state_test
+def test_activation_queue_to_activated_if_finalized(spec, state):
+    # move past first two irregular epochs wrt finality
+    next_epoch(spec, state)
+    next_epoch(spec, state)
+
+    index = 0
+    mock_deposit(spec, state, index)
+
+    # mock validator as having been in queue since latest finalized
+    state.finalized_checkpoint.epoch = spec.get_current_epoch(state) - 1
+    state.validators[index].activation_eligibility_epoch = state.finalized_checkpoint.epoch
+
+    assert not spec.is_active_validator(state.validators[index], spec.get_current_epoch(state))
 
     yield from run_process_registry_updates(spec, state)
 
+    # validator activated for future epoch
     assert state.validators[index].activation_eligibility_epoch != spec.FAR_FUTURE_EPOCH
     assert state.validators[index].activation_epoch != spec.FAR_FUTURE_EPOCH
-    assert spec.is_active_validator(state.validators[index], spec.get_current_epoch(state))
+    assert not spec.is_active_validator(state.validators[index], spec.get_current_epoch(state))
+    assert spec.is_active_validator(
+        state.validators[index],
+        spec.compute_activation_exit_epoch(spec.get_current_epoch(state))
+    )
+
+
+@with_all_phases
+@spec_state_test
+def test_activation_queue_no_activation_no_finality(spec, state):
+    # move past first two irregular epochs wrt finality
+    next_epoch(spec, state)
+    next_epoch(spec, state)
+
+    index = 0
+    mock_deposit(spec, state, index)
+
+    # mock validator as having been in queue only after latest finalized
+    state.finalized_checkpoint.epoch = spec.get_current_epoch(state) - 1
+    state.validators[index].activation_eligibility_epoch = state.finalized_checkpoint.epoch + 1
+
+    assert not spec.is_active_validator(state.validators[index], spec.get_current_epoch(state))
+
+    yield from run_process_registry_updates(spec, state)
+
+    # validator not activated
+    assert state.validators[index].activation_eligibility_epoch != spec.FAR_FUTURE_EPOCH
+    assert state.validators[index].activation_epoch == spec.FAR_FUTURE_EPOCH
 
 
 @with_all_phases
 @spec_state_test
 def test_activation_queue_sorting(spec, state):
-    mock_activations = 10
+    churn_limit = spec.get_validator_churn_limit(state)
+
+    # try to activate more than the per-epoch churn linmit
+    mock_activations = churn_limit * 2
 
     epoch = spec.get_current_epoch(state)
     for i in range(mock_activations):
@@ -44,9 +100,9 @@ def test_activation_queue_sorting(spec, state):
     # give the last priority over the others
     state.validators[mock_activations - 1].activation_eligibility_epoch = epoch
 
-    # make sure we are hitting the churn
-    churn_limit = spec.get_validator_churn_limit(state)
-    assert mock_activations > churn_limit
+    # move state forward and finalize to allow for activations
+    state.slot += spec.SLOTS_PER_EPOCH * 3
+    state.finalized_checkpoint.epoch = epoch + 1
 
     yield from run_process_registry_updates(spec, state)
 
@@ -63,6 +119,38 @@ def test_activation_queue_sorting(spec, state):
     assert state.validators[churn_limit - 2].activation_epoch != spec.FAR_FUTURE_EPOCH
 
 
+@with_all_phases
+@spec_state_test
+def test_activation_queue_efficiency(spec, state):
+    churn_limit = spec.get_validator_churn_limit(state)
+    mock_activations = churn_limit * 2
+
+    epoch = spec.get_current_epoch(state)
+    for i in range(mock_activations):
+        mock_deposit(spec, state, i)
+        state.validators[i].activation_eligibility_epoch = epoch + 1
+
+    # move state forward and finalize to allow for activations
+    state.slot += spec.SLOTS_PER_EPOCH * 3
+    state.finalized_checkpoint.epoch = epoch + 1
+
+    # Run first registry update. Do not yield test vectors
+    for _ in run_process_registry_updates(spec, state):
+        pass
+
+    # Half should churn in first run of registry update
+    for i in range(mock_activations):
+        if i < mock_activations // 2:
+            assert state.validators[i].activation_epoch < spec.FAR_FUTURE_EPOCH
+        else:
+            assert state.validators[i].activation_epoch == spec.FAR_FUTURE_EPOCH
+
+    # Second half should churn in second run of registry update
+    yield from run_process_registry_updates(spec, state)
+    for i in range(mock_activations):
+        assert state.validators[i].activation_epoch < spec.FAR_FUTURE_EPOCH
+
+
 @with_all_phases
 @spec_state_test
 def test_ejection(spec, state):
@@ -73,13 +161,87 @@ def test_ejection(spec, state):
     # Mock an ejection
     state.validators[index].effective_balance = spec.EJECTION_BALANCE
 
-    for _ in range(spec.MAX_SEED_LOOKAHEAD + 1):
-        next_epoch(spec, state)
-
     yield from run_process_registry_updates(spec, state)
 
     assert state.validators[index].exit_epoch != spec.FAR_FUTURE_EPOCH
+    assert spec.is_active_validator(state.validators[index], spec.get_current_epoch(state))
     assert not spec.is_active_validator(
         state.validators[index],
-        spec.get_current_epoch(state),
+        spec.compute_activation_exit_epoch(spec.get_current_epoch(state))
+    )
+
+
+@with_all_phases
+@spec_state_test
+def test_ejection_past_churn_limit(spec, state):
+    churn_limit = spec.get_validator_churn_limit(state)
+
+    # try to eject more than per-epoch churn limit
+    mock_ejections = churn_limit * 3
+
+    for i in range(mock_ejections):
+        state.validators[i].effective_balance = spec.EJECTION_BALANCE
+
+    expected_ejection_epoch = spec.compute_activation_exit_epoch(spec.get_current_epoch(state))
+
+    yield from run_process_registry_updates(spec, state)
+
+    for i in range(mock_ejections):
+        # first third ejected in normal speed
+        if i < mock_ejections // 3:
+            assert state.validators[i].exit_epoch == expected_ejection_epoch
+        # second thirdgets delayed by 1 epoch
+        elif mock_ejections // 3 <= i < mock_ejections * 2 // 3:
+            assert state.validators[i].exit_epoch == expected_ejection_epoch + 1
+        # second thirdgets delayed by 2 epochs
+        else:
+            assert state.validators[i].exit_epoch == expected_ejection_epoch + 2
+
+
+@with_all_phases
+@spec_state_test
+def test_activation_queue_activation_and_ejection(spec, state):
+    # move past first two irregular epochs wrt finality
+    next_epoch(spec, state)
+    next_epoch(spec, state)
+
+    # ready for entrance into activation queue
+    activation_queue_index = 0
+    mock_deposit(spec, state, activation_queue_index)
+
+    # ready for activation
+    activation_index = 1
+    mock_deposit(spec, state, activation_index)
+    state.finalized_checkpoint.epoch = spec.get_current_epoch(state) - 1
+    state.validators[activation_index].activation_eligibility_epoch = state.finalized_checkpoint.epoch
+
+    # ready for ejection
+    ejection_index = 2
+    state.validators[ejection_index].effective_balance = spec.EJECTION_BALANCE
+
+    yield from run_process_registry_updates(spec, state)
+
+    # validator moved into activation queue
+    validator = state.validators[activation_queue_index]
+    assert validator.activation_eligibility_epoch != spec.FAR_FUTURE_EPOCH
+    assert validator.activation_epoch == spec.FAR_FUTURE_EPOCH
+    assert not spec.is_active_validator(validator, spec.get_current_epoch(state))
+
+    # validator activated for future epoch
+    validator = state.validators[activation_index]
+    assert validator.activation_eligibility_epoch != spec.FAR_FUTURE_EPOCH
+    assert validator.activation_epoch != spec.FAR_FUTURE_EPOCH
+    assert not spec.is_active_validator(validator, spec.get_current_epoch(state))
+    assert spec.is_active_validator(
+        validator,
+        spec.compute_activation_exit_epoch(spec.get_current_epoch(state))
+    )
+
+    # validator ejected for future epoch
+    validator = state.validators[ejection_index]
+    assert validator.exit_epoch != spec.FAR_FUTURE_EPOCH
+    assert spec.is_active_validator(validator, spec.get_current_epoch(state))
+    assert not spec.is_active_validator(
+        validator,
+        spec.compute_activation_exit_epoch(spec.get_current_epoch(state))
     )
diff --git a/test_libs/pyspec/eth2spec/test/sanity/test_blocks.py b/test_libs/pyspec/eth2spec/test/sanity/test_blocks.py
index 41316e92d..c2f980ba0 100644
--- a/test_libs/pyspec/eth2spec/test/sanity/test_blocks.py
+++ b/test_libs/pyspec/eth2spec/test/sanity/test_blocks.py
@@ -3,7 +3,7 @@ from copy import deepcopy
 from eth2spec.utils.ssz.ssz_impl import hash_tree_root
 from eth2spec.utils.bls import bls_sign
 
-from eth2spec.test.helpers.state import get_balance, state_transition_and_sign_block
+from eth2spec.test.helpers.state import get_balance, state_transition_and_sign_block, next_slot
 from eth2spec.test.helpers.block import build_empty_block_for_next_slot, build_empty_block, sign_block, \
     transition_unsigned_block
 from eth2spec.test.helpers.keys import privkeys, pubkeys
@@ -253,6 +253,58 @@ def test_attester_slashing(spec, state):
     )
 
 
+@with_all_phases
+@spec_state_test
+def test_proposer_after_inactive_index(spec, state):
+    # disable some low validator index to check after for
+    inactive_index = 10
+    state.validators[inactive_index].exit_epoch = spec.get_current_epoch(state)
+
+    # skip forward, get brand new proposers
+    state.slot = spec.SLOTS_PER_EPOCH * 2
+    block = build_empty_block_for_next_slot(spec, state)
+    state_transition_and_sign_block(spec, state, block)
+
+    while True:
+        next_slot(spec, state)
+        proposer_index = spec.get_beacon_proposer_index(state)
+        if proposer_index > inactive_index:
+            # found a proposer that has a higher index than a disabled validator
+            yield 'pre', state
+            # test if the proposer can be recognized correctly after the inactive validator
+            signed_block = state_transition_and_sign_block(spec, state, build_empty_block(spec, state))
+            yield 'blocks', [signed_block]
+            yield 'post', state
+            break
+
+
+@with_all_phases
+@spec_state_test
+def test_high_proposer_index(spec, state):
+    # disable a good amount of validators to make the active count lower, for a faster test
+    current_epoch = spec.get_current_epoch(state)
+    for i in range(len(state.validators) // 3):
+        state.validators[i].exit_epoch = current_epoch
+
+    # skip forward, get brand new proposers
+    state.slot = spec.SLOTS_PER_EPOCH * 2
+    block = build_empty_block_for_next_slot(spec, state)
+    state_transition_and_sign_block(spec, state, block)
+
+    active_count = len(spec.get_active_validator_indices(state, current_epoch))
+    while True:
+        next_slot(spec, state)
+        proposer_index = spec.get_beacon_proposer_index(state)
+        if proposer_index >= active_count:
+            # found a proposer that has a higher index than the active validator count
+            yield 'pre', state
+            # test if the proposer can be recognized correctly, even while it has a high index.
+            signed_block = state_transition_and_sign_block(spec, state, build_empty_block(spec, state))
+            yield 'blocks', [signed_block]
+            yield 'post', state
+            break
+
+
 @with_all_phases
 @spec_state_test
 def test_expected_deposit_in_block(spec, state):
diff --git a/test_libs/pyspec/requirements-testing.txt b/test_libs/pyspec/requirements-testing.txt
index b5229ae20..e8ecd12a6 100644
--- a/test_libs/pyspec/requirements-testing.txt
+++ b/test_libs/pyspec/requirements-testing.txt
@@ -2,6 +2,6 @@
 pytest>=4.4
 ../config_helpers
 flake8==3.7.7
-mypy==0.701
+mypy==0.750
 pytest-cov
 pytest-xdist