My personal theory as to why this could be is that the film can be punctured with the tiny scratches that form on a screen with normal use. all the reasons Apple states seem to imply that the user is at fault, but the tiny scratches that form when using cleaning cloths and closing the screen should not cause such damage. On my late 2013 15" I have a bunch of little spots of delamination. This is very aggravating because I take verrrryyy good care of this thing. I have 17 battery cycles, There is not a scratch or nick on the entire computer, and I clean the keyboard daily. I completely baby this thing and I still have delamination from gently cleaning dust with a cloth.
How can you have only 17 cycles on a battery from 2013? Have you had it replaced?