I've had quite a few crashes so far but now everytime I try to start the fight it loads for 2 seconds and then crash. Tested it several times now, exact same thing like 5-6 times in a row.
I've run into the same issue I'm stuck on the end of Act 4 now. Gotten stuck before in act 3, I tried creating a new game and loading between the new game save and my main save, also tried traveling between camp and back directly before the battle. Seemed to help or maybe got lucky, got me through a few battles where I thought I was perma stuck. Also running the repair tool might help. Someone said the freezes/crashes are due to an issue with old radeon graphic cards which is might be true in my case.