Liner slipping out of coping

[falken]

You can easily get the liner back in - esp. if it's a) only a year old and b) only 1/4 inch down.
Use hot water to soften the liner so you can pull it back up into place and clip it in.
I've seen people with 15 year old liners use this trick to get it back in place.

I did the same on my 4-5 year old liner.
You don't want to use boiling water, but it needs to be fairly hot. I used hot tap water then microwaved it a few seconds beyond that.
Pour it on the section of the liner that you need to stretch back into place, pull it up and push it back into the track. You will be pulling hard and your fingers and thumbs will be sore by the time are you done.