Mapping intent slots to music artists

Configuration Voice Assistant
1

Hi there,

There is something I do not understand. I have an automation that works perfectly to let squeezebox play my music according to a desired artist:

- id: '1710485725402'
  alias: Sprach Musik Artist
  description: ''
  trigger:
  - platform: conversation
    command:
    - Play songs from {artist}
  condition: []
  action:
  - service: squeezebox.call_method
    metadata: {}
    data:
      command: playlist
      parameters:
      - loadalbum
      - ''
      - '{{trigger.slots.artist}}'
      - ''
    target:
      entity_id: media_player.whutzi
  - service: media_player.media_play
    metadata: {}
    data: {}
    target:
      entity_id: media_player.whutzi
  mode: single

… but to be able to map the voice recognition to certain values that actually exist as artists in my music collection (the voice recognition is not so exact due to different languages of the artists) I try the following in a custom_sentences/de/MyMusic.yaml. (I use this list-mapping also for TV channels where it works):

intents:
  artists:
    data:
      - sentences:
        - "Spielemusik von {artists}"
        - "Spiele etwas von {artists}"
        
lists:
  artists:
    values:
      - in: "(Hubert von Geusern | Hubert von Goisern | Goisern | Geuzen)"
        out: "Hubert von Goisern"
      - in: "Falko"
        out: "Falco"

In the configuration.yaml I use the following intent_script (the first part only if squeezbox is turned off, so the -else- part is interesting :

artists:
    action:
    - if:
      - condition: state
        entity_id: media_player.whutzi
        state: unavailable
      then:
      - service: automation.trigger
        metadata: {}
        data:
          skip_condition: true
        target:
          entity_id: automation.musi_an
      - wait_for_trigger:
        - platform: state
          entity_id:
          - media_player.whutzi
          to: 'on'
        timeout:
          hours: 0
          minutes: 1
          seconds: 45
          milliseconds: 0
      - service: squeezebox.call_method
        metadata: {}
        data:
          command: playlist
          parameters:
          - loadalbum
          - ''
          - '{{artists}}'
          - ''
        target:
          entity_id: media_player.whutzi
      - service: media_player.media_play
        metadata: {}
        data: {}
        target:
          entity_id: media_player.whutzi
      else:
      - service: squeezebox.call_method
        metadata: {}
        data:
          command: playlist
          parameters:
          - loadalbum
          - ''
          - '{{artists}}'
          - ''
        target:
          entity_id: media_player.whutzi
      - service: media_player.media_play
        metadata: {}
        data: {}
        target:
          entity_id: media_player.whutzi
    mode: single

In this setup the playlist is not loaded an no music plays. Whereas it works in the automation above.
Anyone a hint?

Thanks in advance!
Flo