When I examine either to try to load them, it tells me “You need some charcoal to load the clay kiln/rock forge”. I had around 240 charcoal in my inventory, and another 3800 on the ground by my feet. Trying to put charcoal into them directly, it tells me “You can’t place items there.”
It’s moot for the character in question, since she just starved to death, but I’d like to know what’s going on for future playthroughs and other current characters. This was in 0.F stable. Searching has shown me that there have been other problems with them recently, but this is a different issue. I’ve used them in 0.E without issues, but this was my first time trying one in 0.F.