Tire Pressure Light On problems of the 2011 BMW 328

I had installed 4 new tires [p225/45r-17 michelin primacy mxm4 zp tpc spec, run flat] in November 2017 on my 2011 BMW 328i. One year later I started to get tire pressure light on my rear right tire. When I went to check the air, I noticed both of my rear tires were bold like race car tires. I called tire rack to find out about the warranty, they asked me to by new ones and send the old ones back. I am just concern with the condition, if the tires should get this bad before any warning. I have included the pictures of the tires that I plan to return to tire rack.