A common problem, unfortunately. Not limited to Phoenix Cruiser. Owners of other Clear Coated vehicles suffer the same problem.
An earlier Phoenix Cruiser, with 12,000 miles and a California heritage was showing faint signs of blistering when I first purchased. Within the first months of use and before I found inside storage, the blisters expanded to square foot sized bubbles. The coating peeled in sheet sized panels. Polishing compound and an orbital buffer helped by "feathering" the edges.
The PC I replaced it with is now over fifteen years old and blister free. The difference? Inside storage for ultraviolet protection and, at least, annual application of a good wax. I use a marine wax formulated for fiberglass boats.