I've always had a random crash issue on my big map and thought it was somehow mission or possibly event related (partly because I hadn't really edited the missions) and because it seemed to be delayed if I got some sort of event early on (eg candidate for adoption, marriage etc). Makanyane then tried with a smaller map but didn't seem to get the crash so could still be pathing.

I tried running the game automatically using the AI's setup but this used to show the map on the whole screen and then just crash so I didn't know what turn anything had happened on.