At least we seem to be on the same schedule :lol: (I've logged on the past 2 days within an hour of your post)
Again it comes down to 'how does the liner feel when you GENTLY step on it?' - if a little pressure with your foot is met with strong resistance, the liner didn't fully conform to the floor/ bottom cove --- if it feels like jello, then it's water under the liner
I'm thinking that it's the former over the latter. As I figure, you had a new liner dropped on a cooler day (and perhaps even a cloudy day) late in the season. The liner never got warm enough to stretch into those corners and the cold water added to the pool 'locked' it into that shape (I can assure you that even with a heater, you are unlikely to be able to heat the water enough to give the liner the stretch that a hot sunny day would). It is a very new liner and pumping out the pool and resetting the liner on a nice hot sunny day
might/ could fix this - the liner has ~ all it's original stretch still in it. If it's not water under the liner, the liner in those places is under tremendous pressure and eventually being a little too forceful with the brush or vacuum or someone with talons for toenails (

)
will cause a rip
I'm not telling you to drain and refill the pool! But, depending on why the liner is like that, it is an option that
may solve the problem.
Have you spoken with the installer about this - you should still be under warranty :idea:
I wish you well with this and will offer all the help I can to get you to a trouble free pool :-D