I took my Ranger back for the tail light recall and they didn't say anything. Just a puzzled look at the Raptor screen. I did take the tune out of it just in case they updated the ECU.
I have noticed it as well. Seems to be more on the passenger side. I keep trying to clean it and been wondering how I keep missing the same spot :crazy:. I think your right about heat affecting it. My glass does look wavy from a side view.
@Washashore I went the same route as you. I'm having trouble getting the 7/4 connector to lock in on the bumper. It seems so obvious that it should just push in and clip in place but I can't seem to get it far enough in. seems like the bumper pad is holding it out to far. Any idea what I could...