Middgard mod update from 1.1 to 1.2 causes createDeco to crash.

[protected22]

Hi there.

I use the modpack of SbeevYT to play create with colonies. One of the mods in the modpack is Middgard. https://www.curseforge.com/minecraft/mc-mods/middgard. They have updated to 1.2-1.20.1 and after updating to this version. My minecraft keeps crashing. According to claude analysing the crashlogs. this is because of a bug in createdeco.

This is the modpack: https://www.curseforge.com/minecraft/modpacks/createa-colony

this is the response claude gave when I had it analyse three crashlogs:

Crash Analysis
The culprit is: Create Deco (version 2.0.3)
What went wrong
Create Deco failed to initialize with a ConcurrentModificationException — basically, it tried to modify a data structure (a sprite/texture registry map) while something else was already iterating over it. This happened deep in the texture/rendering setup when it was registering its "catwalk" blocks and their connected textures.
The relevant chain:
Catwalks.build() 
  → SpriteShifts (static initializer)
    → CTSpriteShifter.getCT() 
      → StitchedSprite constructor 
        → HashMap.computeIfAbsent() ← CRASH
**Why it's probably a version mismatch**
You're running Create 6.0.8 alongside Ponder 1.0.92, and Create Deco 2.0.3 is trying to use sprite-shifting APIs from those libraries. This version combination appears to have broken compatibility — the internal texture atlas map is being touched concurrently in a way the older Create Deco build doesn't handle.

**How to fix it**

1) Update Create Deco — check CurseForge or Modrinth for a newer version (2.0.4+) that may have fixed this against Create 6.0.8.
2) If no update exists, try downgrading Create to the version Create Deco was built against (likely Create 0.5.x era — but check the mod page).
3) As a last resort, remove Create Deco temporarily until a compatible version is released.

**Secondary note**
The crash report also flags that Embeddium is tainted by sodiumoptionsapi, valkyrienskies, and oculus. These won't cause this specific crash, but if you run into rendering issues down the line, those three are worth investigating.

**What to tell the Create Deco dev:**
The crash is consistent across all three logs — same exception, same stack trace, same line numbers every time:

**Exception:** java.util.ConcurrentModificationException → ExceptionInInitializerError
**Location:** SpriteShifts.<clinit> (static initializer) → SpriteShifts.populateMaps → SpriteShifts.vault → CTSpriteShifter.getCT → StitchedSprite.<init> → HashMap.computeIfAbsent
**Root cause:** The SpriteShifts static initializer is calling into Create's CTSpriteShifter to register connected textures while another thread is already iterating or modifying the same HashMap. This is a thread-safety bug — the static initializer is running concurrently with something else touching the same map during Forge's parallel mod loading phase.
All three crashes occurred with: Create Deco 2.0.3, Create 6.0.8, Ponder 1.0.92, Forge 47.4.18, Java 17.0.8

crash-2026-06-22_08.24.50-fml.txt