Dearest Klei. When I loaded up a save of a game that I last played on August 6th (Volcanea) I discovered that there are now large pillars of 1400C igneous rock inside my base. They were not there when I saved the game after playing it last time. Going into debug mode, I can see that these same extremely hot pillars of rock are scattered across my map. I could go into debug mode to fix this, but I will not be able to earn any achievements during this paythrough as a result.
I have attached a screenshot as proof and am more than willing to provide you with my save file as well as video footage recorded prior to ending my last play session on this map showing said superheated pillars of igneous rock are not present at that time.
Load up a game that you previously played. Large chunks of superheated rock appear all over the map.