This seems to have been a problem for a few users of the PE, it seems it may be due to the LCD cable getting worn down and not working properly(likely due to a faulty hinge), I'll try to find the posts that have more info on it, but so far it seems as though there is no easy fix(that I know of).
EDIT: here is the post:
linkey
My backup has a third page as well, though reading through it can be a bit difficult/weird(you will have to open each reply in a new tab, sorry, not sure why) here it is if you want it:
linkey