inside roof liner "drooping"

[gp2down]

2016 2400W inside roof liner coming loose at the back of the unit...about 3 inches across the width of the unit. Trim is holding it up. Anybody seen this and how did you fix? Thanks

[barnbnb]

The soft touch ceiling seems similar to a headliner in a car or truck: fabric bonded to foam that is bonded to a backing material. What I think you have is the foam layer deteriorating, presumably from heat exposure. That's not good, as it will continue to progress. I have had this experience with a headliner, which required total replacement.
I'd take it to a reputable auto upholstery shop and get their opinion. Good luck!