The first question is why did the bond let loose? Water intrusion is the most likely reason, and, if so, must be fixed first. Simple glue failure is a possibility, but not common in late model RVs.
I don't know any way of re-gluing the wall to the frame without cutting the wall apart, so rivets or screws may be the only option. Or just living with it - it's probably only a cosmetic problem.
Former owner of 2004 American Tradition and several other RVs
Home is in the Ocala Nat'l Forest near Ocala, FL
Summers in Black Mountain, NC