I had the same thing yesterday. Rang local audi to book it in. Got back in my car and it had cleared. Hasn't come back yet.
I had a similar fault pop up on my bmw m135i. Came up twice during 18 months I had it.
I don't see how it can be. The dtuk box is 550 with discount. I don't know if the abt maintains manufacturer warranty but even still I could put £2000 aside to fix anything that breaks if I go for the dtuk box.