After screen replacement, slight discoloration on top right of LCD.

I just replaced the screen on an iPhone 5, and after reassembling it, the screen on the top right (Right above where the display cable bracket is) is discolored, slightly yellowed. It seems like it must be from pressure. When I remove the plate and replace the screen, the discoloration goes away. I have verified that the cable are secured correctly (Camera, digi, and lcd all work), and there's no bunched cables, and all the screws are secured tightly, and there's no give in the bracket, and i made sure the left side of the bracket was hooked under the logic board.

I have had this happen one other time. At that time, one of the screws stripped, and I just had to put it back together without the cable bracket, and informed the guy that if he had any issues, to bring it back to the store and we'd take care of it, but i'd rather actually figure out why it's happening.

The one thing i'm not sure about is the tiny black gasket/spacer underneath the Earpiece Speaker bracket that's in-line with the top screw for that bracket. Could that be on wrong, causing the pressure and therefore the discoloration?

Any other suggestions are appreciated