Why am I always getting tire temperatures "NA" in the pits on some tracks?

[aasasd]

I do some laps, I click ‘back to pits’ in the escape menu, I'm hit with ‘NA’ for all tire temperatures on the setup screen. This happens on some particular mods, and I don't see any way to get the temps to work. Of course, there's the temps display during driving, but those fade off quickly if I stop.

What's going on? Does the track mod author need to do something to get the temps to show? Or do they disable the temps somehow, on the presumption that the crew can't obtain infrared thermometers at that track or somesuch? Is there a way I could turn them on?