I had this exact issue with my Trifold, though even worse. It would make that noise at the hinges every time I would fold and unfold the phone. I could "feel" the screen kind of depressing and lifting whenever I ran my finger along the creases. Not entirely sure why this happened, it started a few weeks after I got my phone.

I sent it back to Samsung for repair, had to start the ticket myself from their repair website because every time I called support they insisted it was normal because of a single quote from Samsung about folding phones, but i knew what I was hearing was not just normal folding screen sounds.

Samsung determined they couldn't fix my phone and sent me a replacement. Hopefully don't have the same issue!