Yea it would make sense that a pocket of gas with really small mass would heat up quickly, come to think of it. On the other hand though, it shouldn't have enough thermal energy in that tiny bit of gas to make dupes melt . Also PVD, better make sure your atmosphere doesn't combust if that keeps up lol.
Been playing for a while, and this is probably one of the stranger bugs I've seen. Every once in a while a superheated pocket of gas shows up near my coal generator, which I placed in an ice biome. Thankfully, the gas pockets quickly cool down, but if a dupe gets too close they get some nasty burns.