Rear Suspension Springs problems of the 2005 BMW 325

I have a 2005 BMW 325xi with 65,000 miles on it. I am told both rear springs are broken. I was also told by the repair shop that this is a much too frequent problem seen on 3 series BMW's. In 40 years of owning automobiles, I have never before had one with a broken spring. This seems like an unusual problem and one that would be caused by faulty equipment.