One thing to check is the caulk on the beltline. The beltline is the plastic type molding that runs around the side of the motorhome and is used to seal the mating surface of the side, top, and front or rear caps. If water gets into the top of the beltline it could run just about anywhere.
If water does get in it will rust the screws that hold the aluminum piece on that the belt line attaches to. Once these rust out it can pull the whole awning off the side.
I am in the process of fixing an area of delamination now on the rear passenger side between the rear window and rear cap. Not an easy job, I'm doing it myself so cost won't be too bad but not for the faint of heart.
2002 Monaco Windsor 38 PKD Cummins ISC 350 8.3L
2005 Jeep Grand Cherokee w/5.7 Hemi