aoc 24g2sp

I recently sent my monitor (AOC 24G2SP) for dead pixel repairing, and when I got it back, I notice that there seems to be a thin layer of air beneath the screen. It is quite visible when I look at the screen from the side (viewed from <90 degree). Is this normal?

Hello, I upgraded from an ACER CB242Y 24 inch 1080p 75HZ to an lg 27gl83a-b 27 inch 1440p 144HZ. I reduced the brightness, contrast, etc - but no matter what I do, i get headaches from it after 15 minutes or so. I went back to my old Acer and now I have no headaches. I do normal work on it...