Mine has gotten worse. Mine has now slumped so low that anything displayed in full screen most of the title bar is off the top and out of sight, and of course the touch calibration has shifted along with it. I have to touch well below the location to get what I want. It seems that pushing it back into position after it has sagged a few times makes the adhesive even weaker. If I had accepted the gap that originally appeared and left it alone it might not be this bad now, or not, hard to say.
I took it out of the frame and this is what it looks like. You can see there is almost no border at the top now. But I don't think it will sag down any more as the small FPC cable for the touch is pretty snug across the top. I think it's holding the glass from dropping any more, or at least until it pulls loose inside and touch no longer works, or the pressure shorts out the FPC cable for the display underneath it, pressing it against that metal edge.
So I don't think I'll be building a revised wood case for it so the orientation is correct, this one is upside down, that's why the cable is at the top. I considered double sided tape around the border to stick it to the frame and hold it up, but if I ever have to remove it I'll probably end up breaking the glass, so that would be a dead end as well. I'm just going to chalk this up as an expensive lesson learned and look for another display to build around when I can come up with the money.