ok I think I've discover the cause of the lift.
Got a replacement due to screen lift and guess what the new one had a slight lift on the lower left.
I figure must be a loose screw, it's not as bad as the old one where the whole left side bulged out.
So I open it and found all the screws to be snug. So I unscrewed the lower left, thinking it's too tight and that's where I discover the cause.
It's not that the screws are too loose, it's that there isn't enough space between the frame & the glass. So the tighter you screw it in, the further you're pushing the screen out, causing the lift.
Here's the simple solution I came up with.
You'll need the following:
Nexus 7 with back cover removed
Pill Blister Pack (Allergy pills from walmart shown)
Scissors and/or knife
Sewing Needle (not pictured)
needle nose pliers OPTIONAL (for those with thick fingers)
First you need to make a hole in the blister for the screw to go thru.
Here I'm using a sewing machine like a drill press to create my hole.
Next, cut out a rectangle and use your small screwdriver (Bigger than the needle, but smaller than the screw)
This will make the hole bigger for the screw to fit. While blister is still on screwdriver, use your knife and run it around the excess plastic created by the screwdriver.
Remove the blister and trim the corners so that it'll fit in the round frame
Remove the screw from the frame and slide the blister in between the frame
Screw the screw back snug, DON'T OVER TORQUE IT!
Right away the screen lift is gone where the blister is installed. Repeat for each screw where the screen is lifting up.
Cut away the excess so you can put the cover back on
Don't cut it flush to the frame, leave a little so you can grab it and remove it if you need to.
OPTIONAL - use a flathead to push that little bit down to eliminate any chance of obstructing the back cover.
Snap the back cover back on and enjoy your flush screen.
depending on how much lift you have, you might have to use 2 or more to fill the gap. But beware, the more you add the thicker the frame will be and you might run into issues with the back cover not fitting snug.