Our neighbor across the street told us it looked like part of the roof over our dormer may have been damaged by wind or hail or tree limb and when we looked up at it, it did look like something was wrong. I didn't have time to deal with it before Christmas, but the other day I went over and took a telephoto picture of that roof and we now are more mystified than ever.
It looks like a piece of roofing shingle, but the dormer roof has a skin type material and our other shingles are brown. It could be that major wind we had a few weeks ago blew someone else's shingle onto our roof. At leas I hope that's it. It's too cold to go climbing up there to see right now.