Didn't see this posted before...
My Kindle fades in the sun...even after about one minute. Very strange...you have to turn a page and then it is partially faded. Turn another one and it significantly fades. Doesn't matter how hot it is. Move it immediately into the shade and turn a page and it's fine.
Wonder why it does this?
By the way, I'm getting a new one. No one beats Amazon for customer service.