Ok, this could be a coupe of different things:
First thing that comes to mind is your hydrostatic relief valve in your main drain. Do you have a main drain? If not, skip this part, if you do:
The hydrostatic relief valve is a pressure relief check valve that stabilizes the ground water table and your pool structure to ensure that the force of water in the ground does lift your pool up and out of the ground completely.
Vinyl liner pools technically do not require a hydrostatic relief valve if they have a sand base floor or a vermiculite soft concrete floor since both of these will allow ground water to absorb through the floor as it needs to, and recede accordingly when the water table drops.
If your pool has a mortar base (sand and concrete) floor, then you do require a hydrostatic relief valve since the water can not pass through this readily enough. If you had a HRV and this was plugged off when the liner was changed, this may cause the symptoms that you have now. Also, if the main drain gasket is pinched or loose this may also cause the same symptoms. Also, if there have been any changes in the water table where you live by recent development in your area, this can also cause these symptoms.
What I am saying is hiring a diver to inspect the main drain will give you more information to work with at this point.
NEXT - it is possible that you do not actually have a problem here. A vinyl liner pool is designed to allow water behind the liner in times of high ground water, like spring for example. It is possible that your pool has been doing this since day one, but you did not notice before because the old faded liner made it difficult to see the definition of the bottom of the pool.
Possibly, if you just leave the water, it will recede on its own when the water table drops later in the year.
My professional opinion is to hire a diver for a visual inspection - someone really qualified.
If this produces nothing, I recommend to leave the problem for as long as possible to see if it gets better on its own. If the problem appears worse, or you are concerned that it is not going away then proceed to a permanent solution. Opening th liner every year will almost certainly cause a problem soon. It is a matter of time before it rips, stretches, distorts or simply will not go back in.
You will need to install a permanent sump pump in the ground behind your swimming pool to a depth of 2' below the deepest point of the pool. This permanent feature is how most pool builders build swimming pools in areas with high water tables.
I hope this information is helpful.
Serendipity Pools & Artificial Rock