HomePod mini (15.1) paired in stereo doesn’t work properly as primary sound source of ATV 4K

When stereo pair of HP mini (fw 15.1) is used as a default audio output of ATV 4K it the sound in videos is always coming from TV speakers only. In the quick menu the source ATV+HP is shown and no possibility to change it. If the default audio output is TV speakers, than you can successfully switch to HP mini in the quick menu choosing airplay icon. Tried everything incl other ATV 4K (fw beta 15.2), resetting everything, reconfiguring home.app. No result :( Looks like firmware bug in homepod os 15.1 or/and TV OS. Streaming audio through any Music app on iPhone/Mac to paired HP’s works good.

On the photo: default output - HP pair but sound is coming through TV speakers only