That's terrible, and I don't blame you for being worried about losing faith.
These things have so many computer controlled systems, (all vehicles do, certainly not pointing at GM here) and I have had a couple of ghosts in the machine. A small issue, cascades into a literal meltdown of other systems, I likened this to the starship in the movie "Passengers" a while back when I had an issue with my 2015 that just glitched out with the hi-beams (unable to shut them off, had to disconnect the battery) and it took the dealer a week to sort out a bad BCM, which caused this break down of other systems. I was fortunately still under warranty as well, albeit the extended, and they figured it out and no issues since then. As mentioned, all vehicles can have issues, it's just unnerving when they hiccup like that and you hope it doesn't happen when you're in the middle of something important. Best of luck, I'm sure it'll work out.
These things have so many computer controlled systems, (all vehicles do, certainly not pointing at GM here) and I have had a couple of ghosts in the machine. A small issue, cascades into a literal meltdown of other systems, I likened this to the starship in the movie "Passengers" a while back when I had an issue with my 2015 that just glitched out with the hi-beams (unable to shut them off, had to disconnect the battery) and it took the dealer a week to sort out a bad BCM, which caused this break down of other systems. I was fortunately still under warranty as well, albeit the extended, and they figured it out and no issues since then. As mentioned, all vehicles can have issues, it's just unnerving when they hiccup like that and you hope it doesn't happen when you're in the middle of something important. Best of luck, I'm sure it'll work out.