I just looked and I found several access doors. On a lark and I took off the one that was easiest to get into. It let me see inside the unit and then I noticed that there is something actually wrong with the screen. The marks still appear when the unit is off and pressing on them causes it to spread a bit, as if there was liquid or a gap or something and your forcing it bigger. It goes back to that size after removing your finger.
I'm perplexed. I don't see how liquid would get into the screen, certainly not on just an isolated portion near the bottom of the unit.