Headlights Turn Off While Driving problems of the 2018 Chevrolet Silverado 1500

While driving at approximately 65 mph all electronics shut off and turned back on moments later. This includes the gauges, radio and all lights including headlights. I took it to the dealership in which I purchased the truck from. They diagnosed it as a low voltage battery and their solution was to charge the battery and retest the systems. However they could not tell me why it was low. The service manager would not look into further testing to check the issue as they had met all the necessary steps layed out by gm under the bumper to bumper warranty. He had told me that they would be happy to do further testing on why the battery had a low voltage condition if I were to pay out of pocket for the costs even though my truck is still under bumper bumper warrenty. The service manager also blammed the cold weather conditions as it is currently in the low 20's outside. I have issue with this diagnosis due to me driving 60 miles a day for work and another 30 miles to drop it off at the dealership, the battery should have been amply charged in that time for their testing. Also the dealership replaced the battery with a new one 8 months prior when I first purchased the truck. I am concerned for my safety as the headlights turned off without warning due to a low battery and there has been no proper diagnosis of why there is a low battery condition.