HomePod with AppleTV won't bring volume to 0

[dmaxdmax]

4K AppleTV with a matched pair of 1st generation HomePods

When controlling volume with the 4K remote, the volume works fine except it won't go all the way to silent, even on mute. The graphic indicates that there should be no audio, but my ear disagrees. It worked fine for months.

Any ideas?

 

[Sheepish-Lord]

I think mine did that as well but I thought the mute button worked…