Bug in group or incorrect usage?

In my group.yaml file, if I say:

  Status:
    view: yes
    entities:
      - sensor.sirenl_battery
      - sensor.siren2_battery

I’ll see two sensors appear under the Status tab. However, if I say:

  Status:
    view: yes
    entities:
      - group.batteries

  Batteries:
    entities:
      - sensor.sirenl_battery
      - sensor.siren2_battery

Only sensor.siren2 appears in the group and sensor.siren1 is missing. Is this incorrect usage or a bug?

Skip the part with “entities” in the group “Batteries” and just have the sensors directly below.

  Batteries:
      - sensor.sirenl_battery
      - sensor.siren2_battery

I don’t know if that’s a typo when copying your configuration file or an actual typo in your file, but notice that your entity is named sensor.sirenl_battery with an L and not a 1 as you wrote below.

Thanks for both comments. Sometimes you can stare at these errors for hours!