So in Final Frontier, the AI doesn't seem to do anything when it turns Avoid Growth on. I am assuming this is likely the same in unmodded BTS, since Final Frontier is DLL-less. While Final Frontier Plus is not DLL-less, I have not modified the code that handles Avoid Growth. If it's not the same, then oh well. Because of the way population and growing works in Final Frontier, it may be more noticeable there- after a certain amount of time the city can't assign any more population to work (since there are no specialists) and so they just clutter up space, causing unhealthiness and unhappiness. The bug seems to be in the way that CvCity::doGrowth() checks for Here is God-Emperor's quoted post on the subject: If this is correct for vanilla BTS, even if the unofficial patch isn't being actively worked on anymore, at least other people can see this bug and maybe fix it in their own mods.