Is it still under warranty of any kind? While it's possible it was stretched during installation and is now coming loose, the way that looks, I'd be worried about a water leak in that area. Especially as the loose portion crosses a panel seam.
Most interior wall panels come with the decorative wall covering already attached, not applied later.
Scott and Liz - Southern NM
2012 Wildcat Sterling 32RL - w/level up (best option ever)
2007 Chevy 2500HD 4dr short bed Duramax w/allison
Reese Fifth Airborne air ride king pin coupler with Sidewinder