I was exploring for some larch wood earlier and found this weird circular hole. This part of the world had been generated a while back, and this hole showed up on the minimap as if it were stone. None of the blocks were touched by me save the top layer block at the far corner. Does anyone know what causes this type of thing to happen? I don't believe it's a peat fire; I don't live around this area and I'm not used to peat generating in this fashion. It is a high-rain area though so idk.