I noticed that my survivor was overheating regardless of clothing and weather, reaching scorching levels in the middle of a chilly night rain. At first I thought it’s just new temperature system being all wonky, but when I cheated in a power armor (it has THERMOMETER flag and thus shows accurate temperature), it showed mere 14 degrees (Celsius).
I checked src/player.cpp for bodytemp and noticed that non-sleeping survivors’ temperature is affected by tiredness. I checked my save: -3721 fatigue. So that’s where all that atomic coffee went.
Maybe there should be some sort of cap on negative fatigue? Excess could go to stimm or even cause some sort of a disease (tremors).
tl;dr Atomic coffee can turn your survivor into a walking (Godzilla-style) biological reactor who sweats superheated scalding steam in the frozen center of a winter lab.