I have seen that happen one time, but it was my front cameras that were blocked but I also then couldn't see anything out the window in front of me. But I was going less than 5MPH at the time, that was less than a half mile from right here on an early morning when the sun was just barely at ground level.I've had side (and rear) cameras blanked by the sun on too many occasions
I have also had sun shine in my mirrors so brightly that they became useless. I assume we have all experienced that as well.
I think when we find the camera won't work because of sun, the mirrors will then also be useless.
Somebody needs to invent something that can see when direct into the sun!
-Don- Auburn, CA