Bug/Issue Furnace not requiring coal

As of yesterday, my furnaces no longer require any coal to smelt!
I have installed quite a few mods, but none of them have any effect on the furnace specifically, but I went through and checked a bunch of configs and manifests anyway.
I have also removed all the mods I installed yesterday and it's still bugged :/ it's not exactly a 'problem' but it does remove some charm by removing a step.

So I'm wondering if anyone has had or seen this bug, if so how to fix it, and if not...then I guess I'm SOL :0