Looks like chunking. Unless you have warranty for tires from BMW they will not cover.

If you need to replace some like the RFT's(Run Flats) because of no spare and many are now running the NON RFT's tires as the
y are more comfortable in ride quality.

Many like the Continental ExtemeContact DWS(Dry, Wet, Snow) tires as the price points are very attractive. Some like the Toyo STII's as well.

I like Michelins Tour HP for non RFT's. I have New Duellers now but will probably move towards Conti's or Michelins non RFT's in the future. I have a repair kit from BMW just in case