just noticed a problem on my a6 avants roof there is a slight bubbling under the paint work on the inner edge of the gutter same on both sides after a bit of detective work i have found out that this is a manufacturing fault apparently it is caused when the metal is creased on the bending machine.the protective zinc coating is rubbed off is this a well known problem and do you think it will be covered under the 12 year anti corrosion warranty i would be very grateful for any feed back