mediaPlayer multiAttributeTile without play/pause/skip controls?

I’m working on a device handler to control Snapcast clients. These clients have volume level and mute control only, i.e. no play/pause or skip.

Ideally, I would use a mediaPlayer tile so that I get the speaker icon that acts as a mute button and a volume slider. Looking at the docs, it seems like I should be able to do this by creating a multiAttributeTile with type mediaPlayer, and only adding MEDIA_MUTED and SLIDER_CONTROL key tiles. However, the play/pause and skip buttons show up even if I leave out MEDIA_STATUS, PREVIOUS_TRACK, and NEXT_TRACK tiles.

Is this a bug in the mobile app. or an undocumented requirement for mediaPlayer tiles?