I created a new world today to further test out my modpack and noticed a lot of Leafcutter ant hills. The game was lagging really bad to I typed the command "/kill @e[type=alexsmobs:leafcutterant]" and it killed thousands at once. This, in turn, caused my game to be less laggy. I flew around the world and noticed the hills were everywhere and spawning more and more ants. I logged out of the world and attempted to log back in which caused my to see a bunch of ant entities for a split second and then the screen went grey (My guess is the game ran out of memory).

Minecraft Version: 1.18.1
Forge Version: 39.0.79
Mod Version: 1.17.1

Mod List: https://pastebin.com/6rVhczFV
World Seed: -1925822649969840498
Log File: latest.log
Screenshots:

I am having the same issue with mod 1.17.4 for MC 1.18.1 using forge 39.1.2.

by the way this sounds like a duplicate of #839