delamination

3M 5200 Marine Polyurethane Adhesive/Sealant might also work. Just not sure how any of these suggestions would work with the foam core.

And to apply pressure to a vertical wall while the glue is setting might be a little tricky. Know somebody who successfully used sand-bags when repairing a Al-Al delam on his roof with 3M 5200, but you will need some sort of cross-brace for a wall.

Epoxy is the adhesive of choice if your materials are absolutely dry.If not Gorilla Glue works well but you have to clamp it so it doesn't push your siding out when it sets.

Yea I had some delamination with our Jayco Eagle also. Traded it in on new.
Good luck,

Gorilla glue expands as it sets. I have used two part, self mixing epoxy from West Marine.Clicky

They have small syringes that work good for injecting it.Clicky

I have read that Gorilla Glue is good for that kind of delam fix. But even though you need some moisture for that glue, you won't be able to do the job right if there is still wet wood.

We had some delam on our slide under the range vent hood. We tried glueing . It looked okay but I wasn't happy and it kept getting a bit bigger. We took it back to the plant and they replaced the whole slide wall for about 1100 and our insurance covered it. Looks like new. I would call Jayco service and ask for a tech to get back to you with the best glue to or the best options.