Hi and welcome to Civfanatics! I'm actually amazed they're building so many. What is supposed to happen is that they can have up to an additional two cities if the conditions are right; this seems to be a side-effect. Unfortunately, I've been unable to add any further civilizations today due to trying to sort out other elements of the mod (though there are still 6 new ones to add to those from the last release). I'm trying to delete Great Writers and thought I'd found a short-cut but it seems not, so back to the drawing board (looks like it's a longer way round I need to go!) There is some good news - I investigated the Death of a Great Writer and found that even with my limited lua skills, I was able to add another option (which is to give the scrolls to his family - basically a "do nothing" option). As this is available 100% of the time (the other options rely on the player have sufficient culture or gold), it will give a valid option to chose and hence prevent the crash. I will still upload what I have later this evening; even if the Great Writers situation isn't sorted, it's an aesthetic issue rather than a game-breaking one.