I am on 1.12.2 using Sponge spongeforge-1.12.2-2838-7.1.10.jar

This is constantly spamming in the console: https://pastebin.com/RX1rvetB
I notice it mentioning extra utilities as well

Astral Sorcery: astralsorcery-1.12.2-1.10.25.jar
Thaumcraft: Thaumcraft-1.12.2-6.1.BETA26.jar
Extra utilities: extrautils2-1.12-1.9.9.jar

From the curse page for Astral Sorcery:
"- Sponge or other server software is NOT supported. Any issues that arise when using Sponge (or other third-party server software other than Forge) that can't be reproduced in a Forge environment will not be fixed. Use other server software at your own risk!"

Please replicate without Sponge involved, also it's erroring because of the exutils fake player having an unexpected registry type, which I don't recall seeing without Sponge, but who knows.

ExU2 is terribly coded.