Sirius is perpetually updating channels
 

Today, the Sirius unit in our ML kept interrupting the music and going into a screen that read, "updating channel list" or something similar to that. I went to Sirius and couldn't find anything about a channel update - let alone having the unit do it 7 or 8 times in a day. These "updates" would take anywhere from 30 to 120 seconds. Do I have a problem, or is Sirius the problem?

sounds like a problem, but I can't say for sure as I'm not a "devoted" Sirius listener

I'd say that is definitely a COMAND issue.

I have the exact same thing in my GL450. My post & some replies here:
https://mbworld.org/forums/gl-class-x164/218353-sirius-updating.html

I had that happening when the car was newer. It can also happens if you are listening to a station for the first time. XM & Sirius build a buffer so when you go under bridges you won't get black outs as often. I also think Sirius has changed some stations recently, I would give it some time before taking it in.