It's called "vibration" and you better get use to it
Your home on wheels tries to self destruct every time it goes down the road. It looks like it's just screws backing out. You should replace any that are missing and check the rest for tightness. If the screws won't tighten then you can replace them with one size larger. Seriously, you just need to keep a constant vigil on ALL of the fasteners on your trailer, as it's a never ending task to keep them tight.
Actually, after looking at your model year you might have nails holding the coroplast. If that's the case you can replace them with self tapping screws. Any nails that are starting to slip down should be pulled out and replaced with the screws instead of being pounded back in. Good thing you caught it early while it's still an easy fix.