I've also applied the upgrade hoping this issue had been fixed in the maintstream packages and AssumeDefaultDomian still doesn't work! Running 32-bit on amd64 and intel.
I'm surprised at this, as I had been running the ppa7 version which fixed the problem but resulted in painfully slow login times and application opening times! Changes to caching settings to speed things up caused lsassd to crash!
I agree with trainerbill's verdict, Ubuntu/Canonical obviously haven't got their act together in tranfersing fixes from ppa release to mainstream release.
This is fast becoming a long running, not so funny, joke! I'm hoping they get this sorted quickly as I'm having to tell my users to use the domain prefix when they login, which also breaks ~ expansion.