A bit before the update I had won against a very strong GW team without losing a character. I fooled around a bit, and then after a while when I tried to start the next GW battle I recieved an error saying the game had to be restarted (this was the update).

When I got back into the game, my progress in GW was pre-win against that strong team, who happened to have a Darth Maul which promtly used his AoE to take out my Jedi heroes like they were nothing. I still won the battle eventually, but this time after losing 3 heroes and halting my progress for the day when I should have been able to continue and earn more War Tokens / Loot.