Volume set to maximum on device when I mute sound in Spotify

[eshcheglov]

Describe the bug When I set volume to "0" in Spotify using both Spotify Web or Mobile Client, DAC volume jumps to 100% instead

HiFiBerryOS version 20201101

HiFiBerry sound card DAC2 HD

To Reproduce Steps to reproduce the behavior:

1. Enable "Spotify Connect" source
2. Start playing
3. Try to set volume to zero using Spotify Web or Spotify Mobile client
4. DAC Volume automatically jump to 100%, however Spotify interface will report 0%

Expected behavior Spotify become muted

I can see this jump using Alsamixer. When I use my phone volume buttons to lower the volume, "DAC" slider in alsamixer correctly go down to "2" but then jumps to "100"