This is a weird one - I have a series of ventilation pipes that have become broken due to cold temperatures, while in ~ 80C plus environment. These pipes carry intermittent natural gas from oil wells in pretty toasty temperatures. I've not had this issue before so perhaps an update quirk?
One gas pump is right next to an oil well kept 'cool' by being partially flooded (so no steam should be produced) and the other gas pump is in a gas trap and only turns on when there is enough natural gas to cover the pump. There is nothing cold in the magma biome currently to get into the pipes.
No idea, as I don't know how this is happening in the first place.