Ok so ive tried flat down.........on the actual screen. It rocks back and forth when pressing opposite corners (top left and bottom right).... when i try other the other 2 corners.... it doesnt move at all...
When i try on the back side with camera off the edge... it rocks as well still. same result.
Your table is crooked.
Do you live in Michigan? They are known to have surface imperfections.
BJ