I had the same issue, bmw looked at it twice and said it was 'a normal operating noise' so I got it in writing.
Hard to hear but you can hear it in this crappy video I made at the start. If I had my gopro back then I could have mounted it right next to the wheel
I got new tyres at a tyre shop and the noise has now gone away.. so bmw could have been tightening them up too hard, or too loose.