Hello,
I was building a new beta1 version of 3.2 earlier today and I noticed that .mo files included in the build are always those from ‘messages’ folder in the Subversion (if they are present there) regardless of which option I choose while building the release (translate.wordpress.org or Subversion). After I have deleted .mo files from the tag I was using for the build, .mo files were pulled from GlotPress. As far as I can tell, .po files are handled correctly. Also, translations for Twenty Eleven weren’t included in the build (tried both options).