2022 Acadia Denali. There is a gap near a front corner of the rear sunroof. The headliner is dropped down about an inch. When I push up it sounds like clips are trying to engage but pop right back out. Dealer service says they can't just reattach it because there is tape holding it up as well as clips and the tape has lost its "stickiness". So they say they have to replace the whole headliner. It's on order. I'm not worried about cost because it's covered under warranty. What I would like to know is if their assessment and solution is correct, or is it bull?