Swimming pools blog

Let’s see if I can explain this.
We have an 18 x 36 IG Pool with a vinyl liner.
Every spring, when we remove the cover to open the pool, we have this problem.
Between the edge of the plastic deck molding and the top of the liner, there is
a molded rubber/plastic insert pushed in around the perimeter. The edge that is
inserted between is barbed and the edge that is exposed is radiused. It is
apparently obvious that the barbed edge, when inserted, is designed to hold it
in place and fill the gap.
When we open up, this molding is OUT of place and only an inch or two is still
inserted in a couple of spots with the rest hanging in the pool.
During the swimming season, from time to time, I go around the perimeter and am
able to press it in a little further into place because it keeps loosening out a
little.
There is one spot along the concrete deck, about 10 inches, that has risen a
little, where I am able to press the entire molding behind the top of the liner.

HOW can I get this molding to STAY in place? Has it possibly lost its
plyability and needs to be replaced? Where would I be able to pick some up?
Leslie’s? Does it come in different thicknesses? (To fill that larger gap I
described) Is there any consequential damage done when this is out of place?
(None is apparent)
We live in the midwest, Chesterton, Indiana, and go through pretty cold
temperatures and snow accumulation throughout the winter. I suspect that that
could have something to do with it. We have a SOLID safety cover for closing.
I’d appreciate any help and if anybody else has experienced the same problem.
Thanks
Arthur