Driver's side rear door window scratch - anyone else experienc?

I have a vertical scratch on the rear passenger door on the driver's side. When window is fully closed, the scratch starts from below the weather strip molding and goes up about halfway on the glass. It looks to me something inside the door is rubbing against the glass when it's rolled down. Anyone else experience anything like this? I'm taking it to the dealer a week or two before my 15k service so they can have the chance to order the part and do it with the service appointment.

 

The scratch was not there when I bought the car new. I only noticed it a couple car washes ago - I first though it was something I could rub off when drying the car, but I can feel the scratch with my finger nail. The fact the scratch runs below the molding strip at the bottom when the window is closed tells me there is something inside the door doing it. The scratch only goes up about halfway so I suspect that it's something in the lower part of the door doing it. It could be a screw not tightened enough, or debris that somehow got inside the door. I generally don't roll down the window except to let the hot air escape after sitting in the sun and never leave it open for more than a few seconds.