Have a 7 seater. Thats the slack in the seat back cable from folding down the second row. You'd only see it if the second row was slid forward.
You can try unlatching the seat back to fold forward and tucking them in as you push the seat back, back up if it's bugging you. I think mine pop out like that.
That said, the back cover on your center seat is popping off on the bottom right as someone mentioned above. That part isn't normal.