At least that's what I believe this is. It's really bad on the roof rails, and I've noticed a little on the front bumper in front of the headlights, which I was able to hide with Zaino. I've tried removing it lightly with a clay bar to no avail, but it does scrape off with a finger nail (you can see a small spot in the picture below).
I don't think there's any way to treat this without sanding/re-clearing, and I don't want to just scrape it all off and do more damage. Does anybody know why this only seems to be happening to the plastic pieces (bumper, roof rails)?
Maybe I'll just get some roof rails if I ever find some.
Pictures:
