That's really odd. I saw those wheels in desert tan and black hardware, looked sick. There is no other alternative to recoating 'em. I don't think there's such thing as sunblock for wheel paint? Just UV inhibitors built into the paint makeup.
Glad you reported this for other's sake. Maybe I'll just get my SVT beadlocks cerakoted tan or something...?
Friend at the body shop looked at them and said they're just cheaply painted/coated. Since they had no real UV protection they were going to fade. Basically, the sun just baked all the yellow tone out of them. They were really nice wheels, and still are perfect minus the paint fade, sadly. I don't think there's any way to prevent them from fading besides them being properly coated to start with. I would not recommend Black Rhino as a company at all at this point. These wheels faded after only about a year and a half, and maybe had about 1000 miles put on them. When I called in they said sorry, 1 year warranty only, and offered no discount or anything on a replacement set.
I ended up calling a local wheel repair/refinishing shop, and to do the 4 of them with tire dismount, blasting them, powder coating and topcoating, remount, and balance was going to be about 1100 dollars. I started just looking around at new wheels, because I wasn't sold putting that much into a set of wheels that I didn't feel were "perfect" for the truck. I decided at this point it just made more sense to purchase new ones and sell the old ones. I found a wheel I liked the design of much better, and decided that the gray would be a better fit for the truck, plus they are Fuel's instead of Black Rhino, so the wheel quality is going to be much better too. Ended up with these:

I've got 5 of them ordered and should be having them installed Thursday-ish.