Mine does that too. When it's off, if I press the Home button, or just turn the volume dial, it comes back on. Also comes on sometimes when I start the truck, even though it's off when I shut the truck off.
If I press the home key on my 2019 Sierra, the radio comes on. It also comes on if I turn the volume dial. This is when it's apparently turned off, not muted. I don't know if it ever gets turned off. The backlight is always on. Is this normal operation?
The dealer told me they are supposed to do that, but I have my doubts.