Mike,
The auto industry has had major problems with clearcoat over the years.
The problem is related to the sun's UV rays destroying the bond
between the color and clear coat paint layers. Once started I don't
think there is much that can be done to stop the process. The current
technology has UV blockers in the clear coat along with other changes
to the paint system which has pretty much fixed things. Repainting is
the only real solution.....

Regards,
Jerry