I have what looks like smudges on the backside of the LCD screen glass. They appear mainly in the left corner but when I photographed the screen while off I saw a few more scattered about. The computer seems to work fine and are only noticeable when the computer is off. I searched the net and one candidate is moisture the other is pressure marks (which isn't well defined). I have pictures https://drive.google.com/file/d/1oILFD5OfNeekIbzsZiQH2RprXW-2qPSS/view?usp=sharing Any advice appreciated.