I converted a spawner to cavespiders (using egg from dna from mobgrinder-mod) and added the fruit to remove ai. I also had added a comparator to redstone control it.
The moment the first spider spawned the server crashed.
I have a few other spawners with no ai and no crash.

I tried doing the same in a creative world and my client crashed as soon as the first spider spawned.
Before removing the ai I spawned a few spiders without any crash.

DW20 1.19 v1.1.1 modpack
Apotheosis 6.0.3

Please share the crash log, Use a site lite pastebin or a github gist please

https://pastebin.com/LAKqS8Y9

I noticed that in this pack spiders move differently (more "natural") might be a 1.19, but more likely a mod...

yeah, this is the crashlog when I changed my creative spawner to normal spiders and it crashed the same
https://pastebin.com/UA17bmNy

FTBTeam/FTB-Modpack-Issues#2449

they seem to have some kind of clue how to fix it in the modpack :)
sorry if it wasn't apoteosis fault <3

It caused by a bad interaction with a mixin from https://www.curseforge.com/minecraft/mc-mods/nyfs-spiders, I tested this with a profile with just apotheosis and was able to get cave spiders to spawn fine with no ai, added this mod and crashed when attempting the same

Its more than just cave spiders

3 crashes with the cave spiders one with the wither skeletons on an airship

crash-2023-02-07_13.40.58-server.txt

crash-2023-02-07_13.19.09-server.txt

crash-2023-02-06_18.50.33-server.txt

crash-2023-02-04_22.39.49-server.txt

The other linked crash is an unrelated CME. The spider crashes are the fault of the other mod's mixin and I cannot fix them, you'll need to report it to them.