Carrier/rack problems of the 2018 Subaru Impreza Wrx

Sunroof exploded driving on highway going roughly 65mph. The car was not driven for 2 days prior due to snow in the area, meaning 2 or 3 inches of snow was sitting on top of the car the previous two days. The night prior to the incident the temperature rose in the area to around 40 degree f. The morning of the incident the temperature was around 38 degrees f. The defrost was on in the car and the sunroof cover was closed. The car is fitted with a sunroof deflector on the roof of the car and roof racks are installed. For debris to hit top of the vehicle from another moving car is very unlikely. There were no overpasses or bridges that were passed under during the incident.