Here's a picture of that holder. The screen fits exactly into the cutout with an opening up top for the cable. Its a secure fit and don't even think it would move without the tape or glue. Thats probably just needed so that it wont pop out before you screw the chip in to the mod. Once it's screwed in, the screen does not move at all. Forms a seal with the enclosure and becomes locked in.
Maybe your screen is cracked and you can't see it without turning the unit on?
That's VERY interesting - how does this little rig connect to the inside of the case? Because the screen is not cracked, there is a solid 2mm gap at the 'top' with the screen recessed at one end and flush to the front of the case at the other. And the gap is all away around and not just the viewable portion of the screen. The way Ginger responded it sounded like the board wasn't snapped all the way in but it sure seems like it is. That picture you post though shows something else entirely. DIY vs built option?
Based on that picture you provide and that little corner - if it's the same design in the build, this makes no sense at all unless some piece of this is warped or the whole mounted board area is at an angle. Given the screws and the TIGHT fit, that doesn't seem right either.
I'm at a loss - Ginger will sort it out to be sure. Given that
@cimon had the same experience, it must be a repeatable one .. -Mags