Tire Sidewall problems of the 2011 BMW 5 Series

My 2011 BMW 550xi has goodyear eagle LS 2 run flats, 245/40. I took delivery of the car in June 2011 and have had repeated bubbles on the front tires. Four tires have been replaced to date. I have never had an issue with tires for the last 20 years. The BMW dealer is not able to say whether it is dangerous to drive on tires with bubbles.

I have a 2011 BMW x5 with the bridgestone dueler h/l 400 255/50r19 107 h. The tires are 8 months old and has driven almost 14000 km. Today one of my tires cracked on a side while I was driving the car at the intersection. I almost got into car accident because of it. When I got home I've checked all my tires and found out that another tire has a bump on a side that will soon crack or blew-out on me. I don't think that it's normal that 2 out of 4 tires are damaged after only 14000 km.

Drove car for only 350 miles from new. Left front tire developed sidewall blister. No significant impact. Noticed damage after returning home from short trip.