For a while, I was doing quite well keeping my base cold by running my ventilation and water pipes around an AETN that I was keeping well supplied with hydrogen, and was keeping itself quite cold. Indeed, I had to be very careful how long I made the water pipes near the AETN in order to keep the water from freezing in the pipes. Recently however, the AETN seems to have a problem keeping itself cold. Even with a regular hydrogen supply, it is up around 60°C and if its hydrogen supply is cut off even for a second, it will quickly heat up. It's like there is a strong heat source near it that it is just barely keeping back. Now it is right next to a very hot space biome, but it has several layers of abyssalite insulation between it and the biome, and the insulation is actually colder than the area surrounding the AETN. I do not what could be causing this heat, but it is messing up my base operations. Any suggestions?
Update: So to kind of answer my own question, a large amount of regolith at very high temperatures seems to be magically appearing below the AETN. Don't know why that should be as there is no path to surface from where the AETN is. Have tried to haul it out, filled up about 10 storage compactors with nothing but regolith, but more of it seems to keep coming. This seems like a bug.
Have an AETN near the surface.