Been discussed here a couple of times. It usually means the radio needs an update. When you shut car off the radio will give you a message telling you an update is available. You can update at that time. The car will need to sit about 12-15 minutes and you cant use it. Once you do update the radio will shut off when you open the door. You do not have to sit in the car for the update. I purchased in September and have had two updates sent to car. Both times I knew it needed it radio did not shut off and then shortly after received message. If you don't get the message, you can, if this is not the issue, use power button to shut it off.
'20's have a dealer installed update available. My dealer informed me of it when I said I had satellite issues when I first got it. It's been behaving OK since last over the air updates but I have to schedule an appointment as it's a 2 hr. upload into it and they prefer I drop it off.
Dealer update via a stick also affects Silverado's per my dealer.
I want all the updates done while it's still in the B to B.