Hm, as far as I can tell, the error doesn't appear to be on my end. The icon size is 32px, and both the item and the furnace entity have their icon_size set to 32 at the data-final-fixes step (when both mods are running). The recycling recipe is also still set properly to use icon_size of 32px, so as far as I can tell, it's not anything I have implemented.
I don't know what that planet mod does, but if it copies items or entities, it might not be setting the icon_size based on the original icon (the default icon_size is 64px when not defined). That's just my guess though, I haven't looked into their code just yet. Unfortunately, the error only gives the name of the sprite, not what sort of object is calling that sprite (item, entity, etc), so I don't know where to look
EDIT: I was just about to write about how I found their error and a proposed fix, but they had already implemented the fix lol
