Minecraft Version

1.21.x

Mod Loader Version

0.16.0

Mod Version

1.2.15

Describe the Issue

When using Medieval Weapons attempting to equip any item in the back slot valid or not the game will crash.
removing Medieval Weapons fixes this issue.

latest.log

https://mclo.gs/CfZ4SW0

Do you use any other mods except the required ones?

No response

Same crash here. Tried to equip a TieredZ iron sword onto the backslot and it crashed.