carrierwaveuploader/carrierwave-mongoid — pull request #109 by did (2013-08-12 22:05:21+00:00)
Title: the call to the default attribute_will_change method was not enough when...

... uploading a new file in an embedded document (#64).

That should solve that very annoying bug: https://github.com/carrierwaveuploader/carrierwave-mongoid/pull/64.
I added a test (all the tests pass).