it's the ceiling in the reflection. you can see the walls and windows end at it. the ceiling happens to be roughly a similar color to the phone making it look like it is peeled or something.
I took a closer look and I think you're right - I can see the outline of where the pillars join the ceiling, as well as smudges that wouldn't be there if it were really peeling. I stand corrected. Was fooled for a minute there though!