It is a design flaw - if you think about the loading on the pin, all the weight is pushing downwards, this gets transmitted through the pin to the plate.
Now, if the plate had been welded to the outside of the panel, it would spread the load beneath it, BUT because they wanted it to look nice and not be a rust trap, the plate was attached to the rear of the panel so all the force goes through the two small spot-welds
In fairness, they've lasted very well considering the age of our cars.
If you can carefully weld it back into place, just gently unscrew the ball and insert a large repair washer underneath it to spread future loads
All Tourer owners should do this BEFORE the mount cracks and breaks
