Hi
I've had this on most of my Audi's but especially the Q5 and the Q3 models. It's not a safety issue but the noise is caused by crap materials used for the discs and pads. The grinding is especially noticeable from cold/first start and can even turn heads of pedestrians as it sounds like metal to metal
You think you're buying a premium product but believe me you're not. If you replace the parts it will happen again down the line as they use the same parts that cause the noise in the first place. There are no modified parts just the same old crap they use from new. Sorry but its a fact. I worked in Audi warranty for years
Never had any brake noise on my wifes VW Caddy at all