Same here. For beta 1 happened when the maps change.
But now for beta 2 I got it 2 times, in the middle of a match.
The log: http://pastebin.com/TBvRmuZD
Yes, with all the maps happens the same.
For me, I get a heavy lag after some vehicles explode, both for beta 1 and 2. But know in beta 2, the game crashes in the middle of the match.
I get this too. On beta 1 it showed in like 20% of the cases when the final score showed up.
But now in beta 2 I get the crash way more often, in the middle of the match and I don't know why.
Thanks developers!