Minecraft Crashes when opening creative tab

[bigdious]

Mod loader

NeoForge

Minecraft version

1.21

Patchouli version

1.21-87-NEOFORGE-SNAPSHOT

Modloader version

NeoForge 21.0.31-beta

Modpack info

No response

The latest.log file

https://pastebin.com/5GzvAR33

Issue description

After porting my mod to 1.21 (from 1.20.5) alongside Patchouli and entering the game, I opened the creative tab but before it could load it crashed the game.

Steps to reproduce

1. Load 1.21 mod with Patchouli dependency and custom book.
2. Enter game world.
3. Open Creative Inventory
4. Crash

Other information

Link to Github source for the mod used alongside Patchouli: https://github.com/bigdious/Risus-Mod

[bigdious]

Updating Neoforge to a newer version fixed this issue.