When I turn the set on, there is a section on the top left and right sides that is discolored. While, the rest of the screen is black (TV warming up), this looks like a faint grayish/white color (not like a shadow problem). It goes away after a few minutes, but I'm afraid it's going to stay on longer. While watching the TV for 10 minutes, I could've sworn I saw slightly on a near black screen. I've had this TV for about a week and a half. Any ideas?