Its happening when you force close on a fight and immediately restart the app and fight. (It may also be occurring for other reasons but this is a 100% way to get this to occur)

Im assuming the server notes the time of the crash(forced or not) and if you are able to log in immediately after and do the fight again the application is marking some flag to true denoting that you are exploiting the system and kabam are trying different ways to punish cheaters/exploiters

Solution # 1: if you force close do not immediately restart the app and go into the same fight. I think you can go do other things like arena or Alliance wars/quests. Im assuming the timer interval they are using to differentiate exploiters and actual crashes is the same 15 minute auto logout timer i may be wrong, further testing is required to verify this.

Solution #2: Don't try and exploit the game.

In summary kabam is holding true to their promise of punishing cheaters and exploiters and if its by the simple method i proposed then kabam may also be logging every time a user is flagged with using a known exploit and can use that data to distribute temporary bans after X amount of times.

Conclusion: Dire.