I'm trying to grind grist in this mostly modless new session I made (the only "mods" used are just "More Athenum Items" and "Expanded Athenum (Modless Multiplayer Friendly", both of them don't add new items, only use existing/vanilla items.) and no enemies are spawning at all when placing new floors & rooms and destroying them vice versa... I didn't even encounter this kind of problem before with those mods.