Theoretically, the md5 mismatch error should not be showing up anymore.
This fix is a long time coming, but it is live, so if any of you have run into the dreaded problem before, please go ahead and try again, and see if you have any problems, or if things work just fine.
I won't go into the technical details here, but it was a very, very deeply rooted problem in our load balancer Perlbal. It has taken months to root out and find, so hopefully the bug fixed this evening was the only thing causing the md5 mismatches. :)