Coil Spring Problem

So I'm changing the front brakes on my 02 Rendezvous, and I notice the coil spring on the passenger side looks 'weird'. I take it to my mechanic and he informs me that the coil spring is broke (as in 2 pieces). The vehicle has only 57,000 miles on it. Anyone ever heard of this? I called the dealership and they seem to think it is 'peculiar', but don't know if GM will cover the repairs (which are estimated at $500, because both springs have to be replaced athe same time). The extended warranty does not cover the spring (but they do cover the strut - go figure!). Any input that anyone can give would be appreciated.

Thanks

DJ