I tested this yesterday and am still dealing with the original issue as
well. To date, I can still say, "Ok Google. Play XYZ song on Youtube
Music" and it will reply with "Ok. Playing XYZ song on (name of CCA) on
YouTube Music" and it is working. If ...
We've been busy at home and I haven't had time to verify working or not
working or fw versions. I'll spend some time tonight taking a look and
send an update.
After your reply, I tried playing something on another music service on
my hub max with CCA set as the default audio device and it worked. Seems
like it does have something to do with Spotify.