Actually I think it's this Papal States Crusading general crashing my game. Once he stops moving, boom, unspecified error. Tried moving him, it still happened. Ideas?
EDIT: not him either. Moved him to Italy, now the game focuses briefly on one of the Papal cities in the Holy Land I gave them (basically recreating the Crusader States, long story) and then crashes.
EDIT 2: Now it appears that the Papal States taking Iskandariyya (left coastal Fatimid city) is the cause? IDK why.