I can't offer you much help, but I'll offer what I can.

1. I'm not clear on exactly what is folding in -- metal wall or vinyl liner. I'm also not clear on what is being "firmly attached" to -- the coping?

2. If the metal wall is 'loose' or shifting at the BOTTOM of the wall, that is a serious problem that must be fixed before you refill the pool. Otherwise the pool will 'blow out' at the bottom. Shifting at the bottom could potentially cause leaning in at the top, though not necessarily in the same place as the bottom movement.