Now it's slipping, a lot!!

Notice the pencil line near the psot, it's slipped quite a bit and only has about 1 maybe 2" of overlap. This is on the one end



Same corner, but from the inside of the pool. Notice the pattern difference.



The sides seem to be OK:



What's odd, is the liner is right up against the wall on the sides, but on the ends it's like 1" away from the wall.

Does it make sense that either:

a) the pool is somehow incorrectly setup making the liner not fit on the ends

b) I didn't overlap enough

c) I dunno? haha

I don't think if I continue to fill it it'll hold. Maybe I should only fill when it's sunny, I dunno. I'm at a loss. If this slips off again,...