It's called tramlining and every car has it to some extent. Having had a 2013 328i with the sport suspension in the past, I can say that I didn't witness any significant tramlining, so it's not inherent to the car itself. It's either your tires or your suspension.
More info here:
https://m.tirerack.com/tires/tiretec....jsp?techid=47
I have noticed in my current car that there was more tramlining when my non RFT Conti CS5 were wearing down near their limits which was greatly reduced with new tires. How old are your tires and how much tread do you have left?
Old and worn suspension components can also effect tramlining and your car is just about that age to start replacing worn parts.