Hi,
i just had an reproducable Endless-Turn-Time gamecrash on turn 370.
By succesively elimination, via Worldbuilder, 1st whole civilisations (Faeries), then cities in the culprit civ (Capital), and then units in the offending city (Gibbon Goethia), i was able to find the unit which made the game crash.
It is Gibbon Goetia's "Changeling" promotion! - If i take this away from him via Worldbuilder, the game will progress as usual and run fine. I do notknow what exactly is going on here, but just that it seems that the AI wants to do something with him which causes a loop/crash.
File is attached, if you want to have a look.