Heos Group support

Hum, strange. Just tested it here again, and working fine both with mini-mediacard and by using services. Here’s my card setup

cards:
  - type: vertical-stack
    cards:
      - type: custom:mini-media-player
        entity: media_player.heos5_office
        artwork: cover
        source: icon
        toggle_power: false
        hide:
          power_state: false
          icon: true
        speaker_group:
            platform: heos
            show_group_count: true
            entities:
              - entity_id: media_player.heos5_office
                name: HEOS5 Office
              - entity_id: media_player.heos1_kitchen
                name: HEOS1 Kitchen
              - entity_id: media_player.heos1_flex
                name: HEOS1 Flex
              - entity_id: media_player.heos_stue
                name: HEOS LivingRoom

And here is how it looks (notice the +1 on the name after I grouped two of the speakers):
image

Does your setup look somehow similar?