If you are looking for warranty coverage, your chances are slim. Coachman sold their RV business last year, so the new owner is probably not going to help. Nor do I think would the old Coachman either.
Most likely the problem is minute cracks in the sidewall, showing through the paint. This has been a fairly common problem with the fiberglass from a vendor who supplied sidewall materials to a number of RV manufacturers. The fix is expensive - grind down the entire wall and resurface and repaint.
In any case, look for body shops that specialize in RVs or boats. They have the skills to do the job. If you tell us the are you are in, maybe somebody can recommend a local shop.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL