The game is not well optimized, it crashes a lot and even closes itself for any reason. When will the next update that will optimize the game come out?
On related note, I've also had more crashes as well since 2.7 and 2.7.2 update, compared to prior 2.6.x versions. I haven't been able to narrow down any specific cause. Can usually restart game, be back in the same battle turn and do same action and continue playing with no problem. Nice job on the save state / restart in same turn logic though