Brake Disc Pads problems of the 2020 Volvo S60

2020 Volvo S60 t-6 r went in for service at Volvo dealer, 5/12/21, mileage 24,018. Technician noted rear brakes less than 2mm & rotors grooved, needs to be replaced. I was told this is not under warranty, it's normal wear. This vehicle had service at the same dealer on 12/8/20, mileage 16,952 the service report stated, "brakes in the green 7mm or more". The vehicle is driven highway miles mainly, regardless of that fact, brake pads don't not wear down 5mm in 7,000 miles on a new car unless there's an underlying problem, there has already been a recall on the rear automatic park brake, seems likely that there's additional problems with the rear brakes. The replacement cost me $888. 00.