As far as I know, it is not a material problem. The problem seems to be that there is a lot of compressible material between the plug and the strap. Once you tighten the strap this material will eventually get rather thin and therefor it may also be a risk with a longer screw. So, the "trick" I've been using personally, is to manually push down hard on the screwdriver the first few turn to avoid the stripping that happened to you.
Once you got the screw to "catch" and have it maybe three-four threads in, then you can tighten it as usual. When fully tightened there will be more then enough thread in the hole for a safe connection.
In other words, the problem is that the system as a whole becomes sensitive to the mounting procedure. At least that is what I think. Maybe Roger has something to add.