Versions

Betweenlands version:

3.4.4

Forge version:

Forge 1.12.2 14.23.5.2815

Singleplayer or Multiplayer:

SpongeForge multiplayer with Velocity proxy server

Installed mods:

All The Mods 3 version 5.12.0
Plugins:
AurionVoteListener
Capacitor (custom plugin for server management and a bunch of other stuff)
CatClearLag
Command Utils
Command Signs
FastAsyncWorldedit
GriefPrevention
LuckPerms
MMCReboot
MMCRestrict
Nucleus
Nuvotifier
Prism
TotalEconomy
UniverseGuard

Stacktrace of issue

https://gist.github.com/NEXUS2345/6b87641cf2a3a0714844fd32b5ce2870

Description of the problem

How to reproduce:

Unsure how to reproduce at this time. Appears to happen only when the Betweenlands dimension is loaded.

This has nothing to do with the betweenlands.
From the looks of it, the recipe for paper is changed/removed and thus printing errors in the log.
Probably a change in the modpack.