I am pretty sure that that is what has happened to the track...last year
when the pool co came to fix the liner pull in deep end, they used lots of liner lock to hold it in....it has been a problem area for several years now. I have accepted that the end is near for this liner anyway(approx 20 yrs old) no more has popped out and the pool is still usuable. ...albeit scary looking in the deep end!

All I need is another 8 wks to get through the season and then we will get it replaced next spring.

My question now is can that tracking be replaced in an older pool? or will the same thing happen when I get a new liner?...is there some sort of retrofit tracking they can add on or something?

thanks for the replies...it had been a long hot day yesterday and I was beside myself!!!