Cheap Chinese Fasteners[maybe?]
Bought a trailer in February. A few weeks ago I noticed one stabilizer was hanging by one bolt. 3 are needed, but the heads broke off 2 self tapping screws. Hate to think what would have happened if the 3rd one broke while driving down the highway. Checked the other 3 and at least 1 head was broken off each stabilizer. Replaced all with rust proof nut , washers, and bolts. Decided to check rails that support the water tanks. Yep heads broken off at least 1 in each rail. Also noticed a ground wire had the head broken off. I replaced a total of 48 of those cheap self tapping screws, with good quality rust proof nuts and bolts.
Suggest you all get out, and get under. Check those fasteners. Cheap insurance.