Error spam on 1.21.3 leading to a crash

After updating my server to the latest buld of PaperSpigot which is the build 60, my console is getting spammed by errors eventually leading to a crash due to the error spam overloading everything.

Server info:

• Here is the error: https://mclo.gs/6eBYref
• ModelEngine version: R4.0.8-dev-all.jar Build 2063 · 2024-11-14
• Server version: 1.21.3