The rear passenger side suspension coil was found broken with a clean break but embedded into the coil boot during a 70k service at the Audi dealer with ~61k miles. No alarming condition of the failure was present, and if it would have dislodged while at speed on the interstate would have resulted in complete loss of control and bodily harm to the driver as well as other vehicles on the road. This was a CPO vehicle garage kept and routinely serviced by Audi, yet they denied any liability and provided no assistance when I escalated to corporate due to being out of CPO warranty by ~2 months. As a result, I had an independent VW specialist shop perform the work, document the observations as if they were to be subpoenaed in the future, and provide me all the parts from the repair (which I still have). The spring coating is completely intact on both rear coils and during the repair process it is evident that the part number has changed from what was originally installed to the current version. The clean break suggests part defect either in design for use or in the spring manufacture. Further investigation on various Audi forums as well as the NHTSA shows this is a prevalent failure for the 2018 Q5 and Audi should be doing something about this.