Probably a random crash… or there were some changes on server side that caused restart.
- Enter a world stage (tried 7.1 with green Carl 6* as ally and 5* Rose leader)
- Switch on auto-play until Carl uses AP gain active skill
- Turn off auto-play
- Long-press on one of team characters to bring up stats (tried 6* Mirabelle)
- When dismissing stats the game restarted
Env: Banks (en) region
Not sure but maybe it was a random crash because I was not able to reproduce again