Just like it says on the tin.

Crashlog: https://pastebin.com/3XFUwfzg

Likely related to the IOOBE obtainable from: #51

Which tab?

GT6 tool+handle tab, a huge, hulking amount of shapeless recipes.

Which tab?

I had a similar crash - Occured when clicking on the shaped crafting for dark steel ingots (non-replicable)
misremembered, was in the dark steel dust shapeless crafting recipe - was able to replicate
https://pastebin.com/Bu3Q20sA

I got a crash too when switching between assembler and crafting table recipe (checking the new bed recipe)
crash-2021-03-22_19.24.48-client.txt

Fixed