I might look into replacing mine with bolts and anchors. I always check them pre-trip and at fuel stops. Now and again I find one or two popped loose. This bugs me as I don't want to break or loose one of the covers. Ideally I'd like to have the same bolt head size as the stabilizer jacks.
You are not adjusting them correctly if they are coming out or undone. I have had not problems after adjusting mine properly. Some were not put together correctly either. 12,000 miles now with no problems.
Moves the expansion part of the rubber in a better position and stabilizes it. Expansion must be adjusted by turning the nut a little on the end of the expansion rubber. When handle is moved over center rubber should expand so the fit is snugged holding the panel well.
I do not think this is done at the factory. Some have no washers also. These keep the expansion rubber from expanding outside the holes.
Southco 19-14-10 is the correct expansion fasteners. (Swell Series) They can be ordered on Amazon @ $10.50 each.
If the factory would install and adjust these before they left the property most of these problems would never arise. Albeit- its is an easy fix and the Swell fasteners are not terribly expensive.