The back wall's is not a delamination. They have what you call a floating wall because the wiring is running back there. There is nothing wrong with the wall's that's the way there built. Check with Keystone and they will state the same thing. I checked beofre buying.
+1 on that....
If you look at the back wall it's not constructed like the side walls.
The Filon is only held in place by the fixtures that actually go through to the studs.....in the large areas away from those openings you will see a bit of wavering.