I had a similar problem with my Flagstaff, as you can read here:
Super Slide separating at floor
I believe the weight of the couch bouncing on rough roads is what actually beat my floor away from the wall, as well as the manufacturer not placing screws in the corner there.....as detailed in the fix in the above forum
I also now insert a wedge between the tt floor and suspended superslide floor when traveling to help support it. Just always have to remember to remove the wedge before extending the slide.