References FTBTeam/FTB-Modpack-Issues#6583 (comment). Looks like the recipe json for uraninite combs got lost somewhere between version 13.6.6 and 13.6.9.

it's not missing in the jar, are you sure the pack didn't just disable it?

How strange. The version that downloaded automatically definitely did not have that file. Copying it over fixed the problem. Unless the FTB team has been manually editing jars, it looks like they managed to archive a bad version of your mod.

I just downloaded from CF and it's indeed missing, very strange as it's present in the local file I uploaded.

Maybe you managed to exclude it from your build path? Crazier things have happened.

it wouldn't be in my local jar if it was excluded

I'll just upload a new build