I think I have the same problem on a 2016 Silverado double cab with 6.2L. Mine happens at highway speeds, but it is very inconsistent, sometimes it doesn't happen for a few days, then it will happen 5 times in a 10 mile drive. Mine has about 1500 miles.
First new truck to, the dealer I found my truck at is 2 hours away. Do I just go into a dealer close to me, or would I have to go to the dealer I bought from?