Perhaps you should re-foam the area? I used a foam/rubber/Mylar 1" thick foam in my engine room ceiling, and after 14 years, it started falling down.
The failure was not the 3-M spray adhesive I'd used, it was deterioration of the foam's surface next to the adhesive. (My foam "sound insulation" was still in good shape, except the foam to glue interface). I removed the sections of foam, coarse brushed the glue on the ceiling to get foam crumbs off, and did the same to the insulation's bad "glued" side. With crumbs removed, and the foam down to a new glue surface, I re-applied the spray adhesive, (3 coats) and stuck it back up there. It worked great, and yes, I may have to do it again in 10 years.
Since your foam has delaminated, you would have to replace it with new insulation, but it might be the solution. IF you want the sound and heat insulation!
first to see if the spray 3-M "headliner adhesive" forms a good bond with the left over adhesive film that is still in there. (Glue something small up there to test.)
If you get a bond, and use the NON "peel N stick" version of foam this time, relying on spray adhesive instead, It should work.