Unavailable entities make card not visible

[smith844]

Found this card today and it appears great. I may be doing something wrong but if seems that if an entity that has been added is not available, ie if it has been turned off, the whole card is not available. I copied the example lovelace card:

entities:
  - media_player.study_speaker
  - media_player.kitchen_speaker
  - media_player.dining_room_sonos
  - media_player.master_bedroom
  - media_player.missing_speaker
name: Sonos
type: 'custom:custom-sonos-card'

but when the media_player.missing_speaker is not available the card doesnt show anything, it appears blank.
Is there anyway of it only loading entities that are available ?