Erratic behavior by HomePods and iMac when using Apple Music

I use an apple desktop (iMac desktop 2021) and a group of HomePod minis to play Apple Music around my house.

Apple Music regularly shuts the HomePods out of the network (connectivity issues have been excluded - I had the IT guy check and the signal is strong). I then have to relink them all. But more disturbingly, one HomePod regularly says random things; in the middle of the night it will laugh, or say, "hmmm..." it will offer random information without being prompted, or suddenly play music un prompted.

Today my iMac has begun to do this in Apple Music. what is going on with Apple Music/homepod minis?