I've got a 2015 Sierra with same problems. Flipping channels, jumping icons, putting calls on mute or hold. Mentioned it to my dealer who said, "Gee I've never heard of this." Immediately realized I was on my own, LOL.
Tried everything. Disconnecting battery, pulling fuses, nothing seemed to work. I ordered a new touch screen and digitizer from Amazon. Very easy to install. Takes about 20 minutes. Drove the truck for 30 minutes following and all seemed well. Next time I drove it, the same problems returned. Coulda put my fist through the screen!
Couple days later after regaining my composure, I removed the screen and digitizer. I took WD-40 Contact Cleaner and sprayed the heck out of everything even spraying it into the CD player.
Two weeks later and so far, so good. Crazy to me how there doesn't seem to be just one fix for this problem. I fully expect a class action lawsuit.