Description of the issue:

Putting any blueprint into the Engineers workbench, results in immediate crash & results in world being un-openable (immediate crash on load).

Crashlog:

From Initial full pack crash: https://pastebin.com/xWWKCxe5
From Minimalist install (IE+JEI): https://pastebin.com/zWfsJ9tW

Versions & Modlist

ImmersiveEngineering-0.15-99
forge-31.2.9

Just managed to find that this was a duplicate of #3908
Closing