Okay, from my experience of working on a 2003MY Polo front springs, the drive shaft to hub securing nut was a "12 point 36mm" nut that had a built in spring tang to act as a locking mechanism, the P/N for that is 6Q0 407 396B - when you remove that nut, you snap off that locking tang - so that explains it all!
Roll forward to 2013MY Polo 6R parts list, that nut used is still the same!
So, as I said, and I'd hope that you would have spotted that if you are working on a car with the same components, that nut has been used so must not be reused as it has now not got a locking mechanism.
Please correct me if I'm wrong.