Quoting Stationary M25 Traveller: When I bought my car from CC it had 32mm long studs which only engaged in the nuts by a few threads ... with the anthracite wheels.
I didn't like the thought of it at all, coming from an engineering background. CC wouldn't have it, so I bought and fitted 40mm long ones myself
You come from an engineering background but earlier in the thread you believe that driving over a pothole causes 4 wheelnuts to undo themselves 😳
To the OP - They weren't done up properly . We've all done it at some point