Button background does not work for light groups

[ando01]

I have a light group that consists of 2 table lamps and am using the standard buttons in an entity card. The buttons work to change the light levels, however the background never changes to show the state. I have verified that the buttons work as expected for the individual lamp entities so I am not sure why the group does not work.

Here is my group in groups.yaml:

  family_room_lamps:
   entities:
     - light.left_family_room_lamp
     - light.right_family_room_lamp

And here is the configuration in the entities card:

  - customSetpoints: true
    entity: group.family_room_lamps
    hiBrightness: 254
    icon: 'mdi:lamp'
    lowBrightness: 50
    medBrightness: 120
    name: Table Lamps
    secondary_info: last-changed
    type: 'custom:light-brightness-preset-row'
  - customSetpoints: true
    entity: light.family_room_fan
    hiBrightness: 254
    lowBrightness: 64
    medBrightness: 128
    name: Family Room Fan
    type: 'custom:light-brightness-preset-row'
  - entity: remote.familyroom
    title: Family Room
  - entity: light.left_family_room_lamp
    type: 'custom:light-brightness-preset-row'
  - entity: light.right_family_room_lamp
    type: 'custom:light-brightness-preset-row'
type: entities

here is a screen shot of the individual lamps in high and the group shows off: