[Bug report] Unoptimized JEI/HEI and Multiblocked causing game to be stuck at loading when trying to add an extremely large multiblock

[Nrmot]

Versions

Multiblocked version: 0.8.5

Forge version:

1.12.2

Singleplayer or Multiplayer:

No, happens before main menu.

Installed mods:

Multiblocked
HEI/JEI

First spotted in CBT New Horizons working on a dev version https://legacy.curseforge.com/minecraft/modpacks/cbt-new-horizons

Link to full crash-report or log

No crash log, game is permamently stuck at loading

Description of the problem

How to reproduce:

Requirements: Have Both Multiblocked and JEI/HEI installed

1. Make an extremely large multiblock
2. Save as multiblock
3. Close game
4. Launch game again
5. Watch for the [Multiblocked] Registering JEI thing in the logs and then see if the game is stuck

Expected result:

Multiblocked will load with no issue

Actual result:

Loading stuck after [Multiblocked] Registering JEI thing

Multiblock in question:

the json file if its named as message 2 text you just rename file extension to json idk im an idiot i passed the code around to my discord server

Why is the multiblock so big?

That's for my custom modpack

Actually

I would be surprised if the multiblock in question loads at all

Also this could be a performance issue when trying to render multiblocks with JEI, game loaded fine without JEI/HEI with the multiblock in question