Hmm, that's interesting. I hadn't heard of Poly-Glow before. It does have the appearance of clear coat peeling at the top of the line. If that turns out to be the case, I have had success sanding the area with progressive grits until I had feathered the clear coat pretty evenly. Then I went over the surrounding areas with a scotchbrite pad, then a shot of clear coat from the automotive paint supply.
Eventually more areas have succumbed to the Florida sun. I plan to ultimately repaint the entire rig a different color scheme.