No fix other than developer driven that I know of, this is just part of the beta process. You and your friend could follow the steps for reporting desyncs though.

** Submitting Desync Information ** » Forum Post by Yarlen

yep, when i don't minidump out of a game, i desync without fail(since the vasari patch).  I play 5v5's mainly, the one time I didn't have so much of an issue was when I played a 4 man ffa.  Even these small games cause regular desyncs and minidumps.

Every online multiplayer game that i've played has had someone minidump, so now i say before a game starts "good luck, have fun, may the minidump always happen to the other guy".

@ logic

well the thing is after a minidump people don't want to restart or might not want to play anymore.  it really destroys the enjoyment of the game.