I was experimenting with a cooler where I have some super-cooled hydrogen recirculating via pipe bridges inside a pipe loop. This was to save electricity on pumping. I noticed that even though the pipes cooled down gradually, the moving gas did not heat up at all. Stopping the gas flow allowed the gas packets to heat up as expected.
Steps to Reproduce
Create a continuous flow of super-cooled gases through a hot environment. Compare with situation when the gas packets stop moving.
This issue has not been confirmed by a developer yet.