Breaking a campfire gives you two charcoal instead of one

Isn't this intended ? You are using logs when you craft the campfire, so once you burn the campfire logs should transform into charcoal

@unknown, yeah. I've also thought about that but it seems to be used as a baseplate rather than "fuel".

Yes, but as the baseplate is wood, the fire should catch and burn slowly the baseplate. So when you remove the camp it had time to transform into charcoal a little bit

you theoretically waste 4 of charcoal / 3 charcoal - coal because you use logs