Oxygen Mask Station warming up way too fast

I encountered this also.  The oxygen mask station was built less than 3 cycles ago in a moderate-temperature area.  It has already heated up beyond its overheat temperature.  I have not yet set any element filters; I don't know if that affects this.

 

I thought this might be because the station reduces air pressure around it, causing heat dissipation from the building to the environment to slow, like how powered buildings in the vacuum of space heat up.  After building a new one and watching it I don't think that explains the temperature rise.  Temperature was already rising fast (about a degree per second) while the surrounding air had >2kg pressure.  Pressure in the area did rapidly decrease as the mask station sucked 40kg of gas into itself, but the area still had ~200g pressure while the building temperature was already 75, only a minute or two after being built.