I yesterday rebuild all metadata again and I removed the createrepo cache. Can one report on the users mailinglist if they still have problems with corrupt checksums ?
If this fixes it, it's a createrepo bug.
As far as I can see everything is OK now, both dag and dries pass through your test after a resync a few hours back (as compared to yesterday when both failed on roughly the same files).
Cheers, MaZe.