diff --git a/crates/primitives/src/transaction/mod.rs b/crates/primitives/src/transaction/mod.rs
index c23d454f86..1edafaaa2c 100644
--- a/crates/primitives/src/transaction/mod.rs
+++ b/crates/primitives/src/transaction/mod.rs
@@ -1478,6 +1478,16 @@ impl<'a> arbitrary::Arbitrary<'a> for TransactionSigned {
                 if tx_eip_4844.to != Address::default() { Some(()) } else { None };
         }
 
+        #[cfg(feature = "optimism")]
+        // Both `Some(0)` and `None` values are encoded as empty string byte. This introduces
+        // ambiguity in roundtrip tests. Patch the mint value of deposit transaction here, so that
+        // it's `None` if zero.
+        if let Transaction::Deposit(ref mut tx_deposit) = transaction {
+            if tx_deposit.mint == Some(0) {
+                tx_deposit.mint = None;
+            }
+        }
+
         let signature = Signature::arbitrary(u)?;
 
         #[cfg(feature = "optimism")]