Have a 2015 F11.....50K miles. Had since new. Full BMW maintenance. In Jan 22 had a problem with the suspension dropping at the rear. Sytner diagnosed leaking air spring but compressor ok. Replaced both Air springs....£900. Last week problem reappeared. Into Sytner again. Compressor failed and has damaged both air springs through the weight of the vehicle. Now require another £2500 I just want to curl up and die. Is this a common problem on the F11 ?