Many older motorhomes will have some fiberglass moisture underneath and you will begin to see some softness to it. More easily seen in different light or from various different directions.
On my class C, I have some very small softness on one side just below the upper window over the cab. I have sealed things up, hoping it last for as long as possible. I thought next time I come across a fiberglass repair guy I would inquire. Certainly they must see a lot of this.
Somebody would be rich if they designed a front plastic cap that would work for aftermarket RV Class C people. (Like the ones you see on the new rigs with no windows)
I too am looking forward to others comments on this....
2003 Ford 450 Jayco Greyhawk 25D
1986 Jeep Renegade
2011 Jeep Unlimited Rubicon JK