Observed behaviour

We've been using this mod for a while and love the mod tho lately it started to crash the server with this error being the first line of the error: java.lang.ArrayIndexOutOfBoundsException: Index 8 out of bounds for length 8
we dont know whats causing it, we asked forge official they couldnt help either.
ill upload our debug log, and heres an MCLogs link in case you'd rather use a paste.
it also happens when certain person joins the server, it allows others to get on but as soon as that person gets on it crashes the server.

this is the Crash Report: https://mclo.gs/CWDBOCE

the debug: https://mclo.gs/GXOyTdT

crash-2024-08-11_04.15.56-server.txt
debug.log

Expected behaviour

Should not crash the server.

Steps to reproduce

not sure

Server Type

Dedicated Server

Crashlog

https://mclo.gs/CWDBOCE

Iron's Spells N Spellbooks version

irons_spellbooks-1.20.1-3.3.0

Forge version

47.3.0

Other mods

No response