Hmm, I can only assume that the problem lies in the Gates parameter, which is also configured in TownExterior and is responsible for the position of the "entrance" to the city. It is likely firmly linked to the main city model and does not work for the new one. But I can't say for sure, I advise you to ask people who made new models for cities, for example, zahar0z or fktifzobr@mail.ru
Added 27 minutes later
for some reason, the Combat parameter disappears for the Castle, which causes the game to crash when attacking; it needs to be set back