Huh, something interesting.
I was using Joker in a fight and had one enemy left with half HP. The game frozen during Joker's Highlight attack and I had to exit out the app and restart.
When I logged back in it put me right back at the last player turn with the enemy having the same amount of HP.
Nice to know if you gotta take a break or do something you can exit the game in the middle of a battle and come back to your previous turn