I experience game crashes after win and before win quote only with certain people. It's frequent, but not 100%.
Since it doesn't happen to me though, I can't give you useful info...
I can say that we both had replay saving off. I can also say the the behavior of the freeze changes a bit depending on who is hosting. If the person who is freezing hosts, he gets the "Error: Connection timed out!" message, and if the person who is not freezing is hosting, the game simply freezes until one of us closes the program. Anyway, not sure how useful or accurate this info is. It's just been my exp with the 2 people i know that this happens to when I play them.