The modpack im playing when this crash occurs is ATM 9 (V9.0.0.51)
The mods version is 1.20.1-2.0.36.1199

When flying around with a twilight cloak (in inventory or curio slots) if a piglin's AI Attempts to attack you. the server will crash with an error.

Steps to reproduce
1: Get a twilight cloak
2: Find a piglin in survival
3: stand close to the piglin (and make sure that the area surrounding is dark) and wait for the piglin to attempt to attack you
4: server should crash near instantly on the piglin seeing you. (you wont be able to get back into that world although you can be Tped out of it into the overworld with a repeating command block)

Server Crash log -> https://gist.github.com/Kavy10/0ac04f94b1cfe1f71eb20e1e444418c5

for an extra note this also affects piglin brutes

(Added this mod to help temporarily fix crashes)
Edit:

Hoglins too!

It's already reported: #640