(Heos) Group Management - activating an entity disables all others

[4s1]

(Heos) Grouping is acting strange.

Whenever I toggle on an entity in group management, which would have 2 entries activated, it toggles off all other entities than the one activated. So I'm not able to activate more than one additional player, other than use group all and deselect unneeded players.

simplescreenrecorder-2024-02-11_16.09.38.mp4

card:
 type: custom:mini-media-player
 entity: media_player.kuche
 group: true
 volume_stateless: false
 artwork: material
 sound_mode: full
 speaker_group:
   platfom: heos
   show_group_count: true
   expanded: true
   entities:
     - entity_id: media_player.badezimmer
       name: Badezimmer
     - entity_id: media_player.schlafzimmer
       name: Schlafzimmer
     - entity_id: media_player.buro
       name: Büro

Fresh installation

• Homeassistant 2024.2.1
• HAOS 11.5
• HACS 1.34.0
• Mini Player 1.16.9