Simple enough. Mixed Metal Ingots do not have a recipe in JEI, yet the recipes are definitely there and working.
Using latest version.
EDIT: Actually, It's all TechReborn crafting recipes. None of them are showing up in JEI. Recipes involving TR machines are working, but ones involving shaped or shapeless recipes are not.

I've been working with VermillionX to identify the root cause.
It seems to be a side effect of updating other mods.
Please wait for more information before pursuing this issue. Thank you.

Interesting, let me know if there is anything you want me to take a look at.

Root cause is Custom NPCs mod.
Tested with version CustomNPCs_1.12.2(20jan18).

Can reliably cause and repair the problem by enabling/disabling only the Custom NPCs mod.
I never would have suspected Custom NPCs.

Interesting, I will see if I can reproduce it

I should add that we had not used Custom NPCs before, so I'm unsure how far back in Custom NPCs releases this can be reproduced.

Using latest TechReborn (from source)
and CustomNPCs_1.12.2(20jan18).jar

It's not just recipes for Tech Reborn that aren't shown, I've seen Immersive Engineering crafting recipes not shown as well.

But this is interesting, perhaps there is an interaction with some other core mod that occurs when Custom NPCs is present.

I can try keeping TechReborn and Custom NPCs while disabling other mods, I'll start with core mods.

I could have been more clear.
I don't believe this is a Tech Reborn bug in any way whatsoever. The recipes of other mods also do not display in JEI.

Ok, ill close this issue. Feel free to open another issue if you find any more issues with tr.