Index: acts_as_attachable.rb
===================================================================
--- acts_as_attachable.rb	(revision 19478)
+++ acts_as_attachable.rb	(working copy)
@@ -125,9 +125,7 @@
 
         def detach_saved_attachments
           saved_attachments.each do |attachment|
-            # TODO: use #reload instead, after upgrading to Rails 5
-            # (after_rollback is called when running transactional tests in Rails 4)
-            attachment.container = nil
+            attachment.reload
           end
         end