Welcome to my world!
In our case my otherwise handy DH measured th wall wrong last fall when we disassembled this (used but new to us) pool.
This spring when I went to order the liner he assured me the walls were 48" tall.
We spent hours upon hours (days really!) putting the pool up, perfecting the sand, laser leveling everything and got our new beaded liner in beautifully. Put our 8" of water in and everything was gorgeous.
Pool water people dumped about 1,000 gallons of water in the pool and THE WALLS BUCKLED!
I was freaking out. Literally shaking. It was still quite some time before we cracked the "mystery." In conversation I said something about the 48" walls and DH says - all innocence - "they're 52"
If I didn't love him so I would cheerfully have strangled him.
So I can tell you with authority that a too-small liner will most DEFINITELY drag the walls down.
I cannot return it (not the manufacturer's fault we can't measure!) so I have a brand new liner in the garage and a new liner on order.
It could take weeks to arrive so we are willing away the pool season with a very expensive sand-pit in our backyard
Let's hope we are all "in the swim of things!" soon!