I a have just took a look at your first photos again and i am not sure but your sliver stuff on the walls looks all creased and it seems to have air bubbles in it too (It should be as flat on the walls as you can possibly get it) its hard to say going off your photos.
That would create hot spots in your grow space. and as you say everything else is as it should be, then all i can think is it may be an environment problem.:hippy:
Just another guess.