i recently build myself a perimeter in my single player survival world. I decided to build a creeper farm in it since i needed to scrap my hostile-mob-farm for esthetic reasons. The creeperfarm is nothing special, smooth stone slabs as platform, anti spider carpet, iron trapdoors to prevent zombies and skeletons, some cats, nether portals and a nice tinted glass roof to be able to see whats going on.
now creeper do spawn everywhere in the farm, but the wont move. No wandering, no turning just standing, doing nothing. They even spawn right next to the cats and dont react. Another weird thing is, that some of the creepers (about 5%) act normal, they spawn, get scared and run off the sides.
I cant recreate this in a creative world. There, the creepers spawn and act normal too. I tried different setups for the cats, minecarts, trapdoors in different hights etc.
I switched my survival world to creative and tried to spawn creepers with spawneggs and its still the same. creepers spawned inside the farm just stand around with the exeption of about 5% wich behave normaly. I spawned some outside and on top of the farm and they show the same beheviour. only going outside of my perimeter mobs start acting normally. could these chunks be corrupted in some way? im not using any mods and its just a normal survival world.
any more ideas, as to why mobs spawn with inactive ai?
It seems to be a problem with the interaction between cats and creepers. In my Farm, the creepers, that are not reacting are all on the upper platforms. So i tested that in a creative world and got this:
It seems like creepers that spawn closer to the "ground" behave normally and going up the AI just breaks.
I'm not sure this will help, but creeper farms generally need a targetable block for the creeper to attempt to wander/flee towards on the other side of the drop — like the outer rim shown here (Creeper Gunpowder Farm Tutorial | Minecraft 1.14 - 1.17 (Java Edition) by LogicalGeekBoy).
This would not affect creepers on platforms low enough to be tracking the grass on the ground.
From you initial post, it sounds like you are moving the creepers out of the farm via nether portals rather than a drop; are there area on the other side of the portals the creepers wander AI would consider targetable (e.g. carpeted full blocks)?