Yo, Gfresh - welcome to The Forum!

With high ground or 'surface water issues - I'm gonna double down and say that it is the wall foam. (I'm assuming that we are talking about the walls of the pool)

With a 3 year old pool and a liner that hasn't been chemically abused, you could easily fix this... it would require draining most of the water to do so.

It's getting late for me, so I'll leave it at this and await a response.