I'm trying to change the history for the county of Oshrusana in the duchy of Samarkand, but even if you make one small change things start acting weird. At the start screen the county becomes ruled by the king of Transoxiana, and if you check the county's history in-game, all other rulers disappear. There seems to be a similar problem with the counties in the duchy of Fergana, but I've never seen this problem anywhere else. Is there something hardcoded?