Why did the ZA-35 lose its thermals?

It has a IRST system, meaning it SHOULD have thermals. and it DID have Thermals. Why did it lose them?

It never had thermals ingame.

It did, I remember test driving it and using the Thermals.

How long ago was this? I’ve been using it for a long time, never once with thermals.

Also, those two are separate things. Not all IRST trackers are also thermal sights, look at the IRST used on fighters.