I got the same issue that RenoGeek. I just failed the Local Hero Quest, and the game stopped working.
I'm playing in a iPad Mini 2, bought the season pass and I was logged out. I think the problem is with the save file, because I can start a new game and is working fine. I just cant play with my old save file after Local Hero. The interface is frozen.
Also, if a character dies in a quest and you win the reward is lost, even if you replay the scenario. Is a shame because I love the game, but now is almost unplayable.