Always get a new object on edit, update and delete.

app/controllers/devise/registrations_controller.rb

@@ -30,28 +30,28 @@ class Devise::RegistrationsController < ApplicationController
 
   # PUT /resource
   def update
-    if self.resource.update_with_password(params[resource_name])
+    if resource.update_with_password(params[resource_name])
       set_flash_message :notice, :updated
       redirect_to after_sign_in_path_for(self.resource)
     else
-      build_resource
-      send(:"current_#{resource_name}").reload
       render_with_scope :edit
     end
   end
 
   # DELETE /resource
   def destroy
-    self.resource.destroy
+    resource.destroy
     set_flash_message :notice, :destroyed
     sign_out_and_redirect(self.resource)
   end
 
   protected
 
-    # Authenticates the current scope and dup the resource
+    # Authenticates the current scope and gets a copy of the current resource.
+    # We need to use a copy because we don't want actions like update changing
+    # the current user in place.
     def authenticate_scope!
       send(:"authenticate_#{resource_name}!")
-      self.resource = send(:"current_#{resource_name}")
+      self.resource = resource_class.find(send(:"current_#{resource_name}").id)
     end
 end