Universal media player only controls first instance

Configuration
1

I have 3 Sonos devices which can be controlled independently. However, I like to group them and easily control the volume from one slide bar.

Have the following set using the Universal plugin

  - platform: universal
    name: Sonos All
    children:   
      - media_player.living_room
      - media_player.kitchen
      - media_player.bedroom

This is fine and it displays a single instance of my Sonos under media_player.sonos_all

However, changing the volume only affects the first instance media_player.sonos_living_room, it ignores the other two. Changing tracks and playlists works fine.

I am sure this used to work. Can anyone help please why the volume doesn’t work properly?

Thanks

2

Anyone? Thanks