Another data point to add to this topic: I have a 2020 Chevrolet 2500HD with the 6.6 gas engine. Currently at 28,000 miles. I change the oil every 5,000 - 6,000 miles, as I primarily just use the truck for towing. Oil and filter always changed at the dealer.
I took it in this week as I was getting white smoke on cold start on warm days (70F outside), which was concerning. Dealer confirmed they think it is burning a little coolant, but also notified me I was down a 1.5 quarts of oil (5,000 miles since my last oil change).
They told me to keep driving it and they would "monitor it". I am aware GM released a service bulletin about excessive oil consumption, and that losing 1 quart of oil every 100 gallons is normal.
