It is not registering the JEI plugin as shown in the Logs.
Most probably because it is a large Modpack as when alone it registers the plugin.

https://www.pastefile.com/1CxNAu

the Log in this issue is the same:
#142

AbyssalCraft vers: 1.12.2 1.9.4
Jei: 4.8.0.110
Forge 2515

Mods list:
https://pastebin.com/xUm2RQJy

@Shinoow I think I found the problem with the JEI Plugin. Thermal Foundation is somehow causing this problem as I have just these mods in it. Craft tweaker was in there for just the mod list. I did test it without Thermal Foundation, and it had no errors and I had checked all the COFH Mods separately so the cause is "TF"
I can send an issue to COFH if this isn't your mod interacting badly with Thermal Foundation

Mod List: https://pastebin.com/SPJb5vzy
Error Log(since there were no crashes): https://pastebin.com/Kv0WbsKa

OK, thank you! and no problem.

Descending even deeper into the code, it seems that the item in TF OreDicted as crystalRedstone somehow bypasses the filtering of invalid fuels in my JEI plugin, which then results in the plugin stopping it's registration as something with the value of 0 is passed as fuel.

EDIT: taking a second look at my code, it never checks the filtered list prior to adding it to the list of fuels, therefore relying on the unfiltered list of Ore Dictionary entries to have valid entries only. I'll apply a fix for this and release an update with it today!

Thank you again Shinoow.

I looked around in their code, and the reason it's happening is that they register their crystal items to the OreDicitonary as crystal<something>, which clashes with my crystal items, as both mods add their own Redstone Crystal. This is entirely on my end, as I didn't take this possibility into consideration, so I'll be the one patching things up on my end!
Thank you for looking into it!

it Works! 👍 💯

Seems like something is bypassing the initial scan and filtering of potential fuels. I know JAOPCA does stuff with crystals, also adding them as fuels, so in the event that mod is the culprit, you should be able to disable the compatibility in that mod's config file, or temporary remove it and see if that solves it. I'll look into tightening any holes in my JEI plugin.

ok thank you, I'll see if that fixes it temporarily.
It doesn't seem like its JAOPCA as I just removed it and it still does the same thing.
This is still shown in the logs.
https://pastebin.com/XYLEfrP3

Full log:
https://www.pastefile.com/YqQlSO