Air between liner and the wall of the above ground pool.

[PoolSheri]

SPLIT FROM Air pocket around the wall of the above ground pool.
I have same problem and it’s all the way around evenly. Mine is above water level only emptied and refilled 2 days ( very slow draining) high 60-low 70 temps kept tarps over walls to keep sun off

 

[zea3]

I have same problem and it’s all the way around evenly. Mine is above water level only emptied and refilled 2 days ( very slow draining) high 60-low 70 temps kept tarps over walls to keep sun off

I think in your case it may be because you didn't set the liner with a vacuum before the water went back in. Its not a super big deal as long as the pool is full.