The crackling/crazing is most likely as read & learn described - an actual defect in the fiberglass under the paint. It happened to dark colors exposed to hot sun and results the material itself rather than anything the RV manufacturer did with the paint. It's a cosmetic problem - no water gets in or anything like that. It can be sanded down to the fiberglass and repainted for around $10k-12k, but the problem may re-occur after some years (depending on sun exposure again). Or the sidewall can be completely replaced with an improved fiberglass, to the tune of about $30k-$35k. A buddy of mine had his dark blue 2000 American Dream sanded and repainted (under warranty) and it has held up fine, but others say they problem has returned. My 2004 (black & gold0 has a touch of the crazing on one side, but I'm just living with it. You have to look close to notice it.
Some rigs that had this problem were Fleetwood & American Coach, National RV, Alfa, Country Coach and probably more. They all used fiberglass from the same supplier, and experienced the same problems with dark colors.
Former owner of 2004 American Tradition and several other RVs
Home is West Palm Beach, FL