Mod Name
More Furnaces

Link to the mod (ideally Curseforge)
https://www.curseforge.com/minecraft/mc-mods/more-furnaces

Support for this was added in #176 and this worked in MC1.12.2_v1.0.6, however the GUI is mangled in MC1.12.2_v1.1.0 (all slots are offset significantly from the visual slots along both X and Y). This was noticed in Omnifactory, which uses the most recent 1.12.2 version of More Furnaces (MoreFurnaces-1.12.2-1.10.6.jar and cxlibrary-1.12.1-1.6.1.jar)

Related to e44afbb possibly

I wonder if this issue come from this resource pack. Even without it, the GUI for the furnaces seem to be a bit misbehaving. I have seen it disappear for no reason. (Though I haven't seen the offset issue without the resource pack)

Removing the .json files from the directoy seems to have solved the issue for me.