Title pretty much sums it all, if you have 2 different gases, even regular and polluted oxygen, they will transfer absolutely zero heat between them, when they should still even out.
In screenshot 1, you can see I have a pretty standard sandwich of gas, oxygen on the bottom, some polluted oxygen off the polluted ice in the middle, and runaway hydrogen on the top. In the second, you can see the clean oxygen literally next to the polluted one keeps its toasty 24 degrees, to the -22 degrees of its neighbour.
Steps to Reproduce
Have 2 or more different types of gas in a room, then produce some heat; watch only one of them get hot.
This issue has not been confirmed by a developer yet.