command ventilation_supply_only doesn't work

[Hans-0]

The following snippet of my comfoair (Q350) yaml config doesn't work. A similar snippet for the extract_only does work fine.
Is there anyone who has an idea why this (ventilation_supply_only) doesn't work?

SNIPPET: ventilation_supply_only

  - platform: template
    name: "Supply Only"
    id: comfoair_supply_only
    optimistic: true
    options:
      - "off"
      - "activate"
    set_action:
      - lambda: |-
          if (x == "off") {
            id(comfo).send_command("ventilation_supply_only_reset");
          }
          if (x == "activate") {
            id(comfo).send_command("ventilation_supply_only");
          }

SNIPPET: ventilation_extract_only

  - platform: template
    name: "Extract Only"
    id: comfoair_extract_only
    optimistic: true
    options:
      - "off"
      - "activate"
    set_action:
      - lambda: |-
          if (x == "off") {
            id(comfo).send_command("ventilation_extract_only_reset");
          }
          if (x == "activate") {
            id(comfo).send_command("ventilation_extract_only");
          }