My display will make a "clicking noise" (multiple times some times without changing the display) but then will sometimes change the Info display to the Music display. I have had the OnStar activation screen come up on the middle dash display. Lots of crazy "ghost" display changes like those mentioned here.
My non-dealer mechanic suggested doing a hard reset by unhooking the battery for up 30 minutes. This action helped solve a similar problem his son was having. I will try anything before spending MORE money. I will let you know if this works for my issues.
Note: just replaced transmission with less than 88K miles ... losing confidence in several design features for my 2017 Silverado 1500.