Audi and all their operatives have to be very careful when answering questions like "Have you had many cars in with XYZ fault" as any reference to "We do get quite a lot" could be taken as an admission of guilt. I do understand Audi staying well clear of this one as to fix the fault costs a fortune in labour never mind in parts.
As a final note before I get thoroughly bored, there are several posts on this thread made by mechanics who clearly know their stuff. Their knowledge and experience surpasses mine and I daresay yours.
It's rare I come across posts that, to me, appear troll-like but this gets added to the list.