This is rather strange. It seems to only happen in scenarios. I was testing around with some of my older maps. And the map had pretty standard-setting, 3 villagers, and a town center. The AI has the bright idea of deleting their own town center. I don’t think it’s trigger-related, since I didn’t edit any HP of any unit, nor did I use damage object.
It seems to be the same case with many scenarios, and I assume it’s the same case with other maps not of my own. I don’t know if players in-game will do automatically either. I liked to test my maps with AI sometimes. I played some of these maps of mine fine in the past, and nothing like this happened before.
Recent map of mine where it happened: Mods Single – Age of Empires