Almost lost a mud flap...

I had a very similar experience except with a bit of a twist. We stopped at a Rest area and I also noticed that my rear passenger side Mud flap was somehow wrapped up around the tire into the wheel well. I played hell trying to pull it back down into place(the mud flaps are a bit cumbersome and stiff). I finally was able to do it and move on down the road. Now here's the twist....about 1000 miles later while looking again, the center tread had separated from my inside dual(completely gone) which was the cause of the Mud Flap incident. The tire itself was still holding pressure but entire center tread was gone! I now make sure I look carefully at my tires and not only for correct pressure.