Liners have a shelf life. Installers can order a "Winter Cut". This means it's slightly larger than a regular cut liner. Since the water and air are low temps, the liner's ability to stretch is reduced. The Winter cut allows for this so the liner fits correctly.
Do NOT leave that pool empty and uncovered. That is a serious safety concern and can damage the pool too. Remember, Murphy is watching! If someone slips and falls in unnoticed, like a kid or a dog or a deer....
While replacing the liner, pressure test the lines. You can get to the drain easily when it's empty. You can also change the drain cover to a VGB compliant one.
Scott
PoolGuyNJ