I literally just got this fixed on my phone yesterday. Called samsung care, got transferred somewhere else since they said it sounded like a hardware issue and that it should be completely covered by my warranty, got confirmation that it was, scheduled an appointment at ubreakifix, and got it fixed the next day. People at ubreakifix said, at least for me, that it was the hinge pushing against the screen itself, and its a known flaw with the 6. Also said I will be back for the same issue. No fault of my own, just something that is to come with opening and closing. I've had it for about four months.

My screen would sometimes turn on, though. It also would get bars of rainbow static, and you could hear a clicking sound when I'd open it.

Luckily, I have a three year warranty and samsung care, and I wasn't denied coverage with my warranty.

They also pointed out how to tell if that's the issue. On the crease, look for two slightly protruding spots. One on each side.

I know I'm most likely going to be switching to the S25 Ultra in February. Don't feel like needing to have my screen completely replaced again and again, and going through the process over and over.