This issue was discussed on a Facebook page: Thor Quantum Owners Group.
After reading that post, I inspected our 2017 Quantum KM24 and discovered the same problem.
A member of that Facebook group advised that he had used Liquid Nails, applied with a caulk gun to squirt the substance up into the areas of de-lamination, then clamped the leaves together and applied waterproofing.
I also squirted Liquid Nails and clamped together and applied a marine varnish once dry.
I also sealed with Gorilla Tape and then reattached the trim piece.
I did contact Thor when I discovered the issue on our coach and as it was still under warranty they agreed to repair the problem.
I have an appointment at the Factory Service Center in early October.
My fix was only temporary as we were preparing for our summer western RV odyssey and I could not get to the factory before departing.
So far it seems to be holding up but we have yet to encounter any heavy rains.
The worst damage was on the driver’s side but I did the repair to the passenger side as well.