Some time ago I did not use the Gen3 because of the problem of the screen.
Yesterday, after rapid reading, put the Gen3 near the ice pack he was wearing. When I turned on the Gen3, the screen seemed whiter. I put the bag on top of the screen for some time, and the screen was like new.
The higher the temperature of the screen, the lower the contrast, the screen gets too dark. At room temperature (27 degrees (C)) reading is markedly impaired.
I do not imagine the cause of this problem.