Just had a problem with 2 iox lenses , red sensor and blue sensor. Called smith and they immediately said send them in and we will ship you new ones.
I also sent in my red sol x for evaluation and they sent a new one of those too. Fwiw I never had the problem on the blue/red sensor mirrors until the temps dropped below high 20s. Coincident not sure ......
Had I/o for a season and never had any issues with between the lens fogging.
Wife had iOS and never had a problem in 2 seasons.
Tell you one thing..... The IOX lens, when not defective, will not fog. Not even with a face mask and hot breath out of your mouth going straight on the lens.