[JRTJH]

The rear panel is a "free floating FILON sheet". It is fastened around the edges, at any window/vent openings, at the tail lights, grill mount (if on your trailer rear wall) and any other accessories that are mounted on the rear wall. Otherwise, the rear FILON "floats" and is not attached.

Often when the sun heats the FILON, it will expand and "oil can" (buckle). That is normal and to be expected. As for the panel "slipping down" and separating at the top, that is not normal and should not occur. If it has pulled out from under the top molding, then it needs to be repaired and properly sealed to prevent water intrusion. This may be partially covered by your insurance and/or extended warranty (if you purchased one).

Repair (sooner rather than later) will prevent further damage from moisture. If you can post pictures, they should be helpful to anyone who has had similar problems. They could identify what has failed and offer repair suggestions that worked for them.