I noticed my screen doing this last night, with hardly any pressure.
On the sides it's really easy to get it to discolor, I can do it with my pinky with a little more than "normal" pressure.
I compared side to side with my cousins from Verizon, and the amount of pressure to get his to discolor is about 10x more than mine.
I can also see 3 black lines on each horizontal side of the screen when looking sideways.
The backlight appears to be bleeding through the top.
Going to go to T-mobile tomorrow and get it replaced, along with my cousin to make sure they realize it's not supposed to be that easy.