In the recent GTNH update 2.5.1, it's not possible to use machine crafting recipes. You can't use the "?" button to fetch crafting recipes from NEI (Not Enough Items) for machines; only basic vanilla recipes can be fetched. Sometimes, errors may also occur.

Yeah, GTNH rafactored the recipeMap of the GT5. I'm trying to fix it.

I have the same issue, i found that GT-Unofficial marked Deprecated at GT_NEI_AssLineHandler in last year(https://github.com/GTNewHorizons/GT5-Unofficial/blob/9a2741128a78bb52eba50a631126e090a5a2abd8/src/main/java/gregtech/nei/GT_NEI_AssLineHandler.java).
And this class is be deleted in current.

So i think this code need to update: https://github.com/Towdium/JustEnoughCalculation/blob/19fb4c49c32e53c8fa19a6bc79297de2a6876d93/src/main/java/me/towdium/jecalculation/nei/adapter/GregTech.java#L65C1-L65C1
I don't know where is the GT5 code move to, so in my opinion, just need predetection getAssLine not be null then to check recipe is its instsnce or not.

New version have been published to CurseForge and Github releases