Packets error 1.17

[TheDame]

General Information

ViaVersion dump url: https://dump.viaversion.com/971bad796aeec688e87b3c5675f1f22370e13808ae88d958f9051ceca8799734

Bug Description

Please do not ask about the other mods mentioned in the dump URL. Anyways, when I try to join a server using ViaFabricPlus set to version 1.17 with the real version being 1.21.1, it gives me this error:

The server I was joining was Advancius Network. Also worth mentioning is that at first it works, but as soon as I enter any gamemode, it gives me that error.

Steps to Reproduce

1. Join server "mc.advancius.net" on 1.21.1 with the version set to 1.17
2. Enter any gamemode
3. Game crashes

Expected Behavior

The game should not crash when I try this