1 files changed, 7 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/autosave_association.rb b/activerecord/lib/active_record/autosave_association.rb
index 0792d19c3e..5f38bd51f6 100644
--- a/activerecord/lib/active_record/autosave_association.rb
+++ b/activerecord/lib/active_record/autosave_association.rb
@@ -222,6 +222,7 @@ module ActiveRecord
               true
             end
             validate validation_method
+            after_validation :_ensure_no_duplicate_errors
           end
         end
     end
@@ -456,5 +457,11 @@ module ActiveRecord
           end
         end
       end
+
+      def _ensure_no_duplicate_errors
+        errors.messages.each_key do |attribute|
+          errors[attribute].uniq!
+        end
+      end
   end
 end