Failed to encode packet 'serverbound/minecraft:set_creative_mode_slot'

[royal pecan]

@amber hemlock uploaded a log, Frequently have issues with switching hotbars on my server where I lose the hotbar after switching to it and get kicked. Makes me so sad when I have important items in those hotbars

Minecraft version 1.21.4
Fabric version 0.16.10
Mod name and version Axiom 4.4.0
Any relevant error messages or screenshots: 
Server: Current Purpur Version: 1.21.4-2384-79c1192 (MC: 1.21.4)*
  Had same issue on Previous: 1.21.1-2329-803bf62 (MC: 1.21.1)
Spark: https://spark.lucko.me/CbalZFZgIt

• Fabric 0.16.10 on 1.21.4 using 37 mods
  Recommendations:
• Unless you know what you're doing, modifying your JVM args could have unintended side effects. It's best to use the defaults.

[shrewd wave]

Send .minecraft/logs/latest.log

Also send the server logs

Are you using a mod or datapack on the server that removes enchantments?

[royal pecan]

@amber hemlock (Qchex) uploaded a log, Minecraft: https://mclo.gs/71O0obc

• Fabric 0.16.10 on 1.21.4 using 45 mods

[amber hemlock]

I don't believe any of these datapacks should be removing enchants. No plugins present should either

[shrewd wave]

graves might be

[amber hemlock]

Server Log: https://mclo.gs/ht1rPFv

Graves does a lot of stuff that I've had to work around, I think I need to replace it

[shrewd wave]

Graves removes the Curse of Vanishing enchantment, seemingly

Hm actually it's not just that, it's also knockback?

[amber hemlock]

Maybe it doesn't play nice with 'illegal' enchants

[shrewd wave]

Anyways, looks like some datapack is messing with enchantments and your hotbar contains an item with those same enchantments

[amber hemlock]

I see, its odd because most of the time I can switch on and off of hotbars but sometimes after restart I'll have this issue. I'll try to find a replacement for graves, thank you!