Here's a video of the XM cutting out issue.
While driving in a northerly direction and the sunroof is open, XM keeps cutting out. This video covers 1 mile of road. I count at least 8 times the signal drops out completely.
Driving south or with the sunroof closed, there are zero drop-outs.
Sorry for the classical music, but YT kept ripping out the audio when I tried pop music.