Same problem with BubbleUpnp m4a playback through my Naim UnitiLite and Tidal stream of The track J ai fait un promesse by Anathema,
album Serenades. It does not play any m4a except if ffmpeg option îs activated for all tracks.
Except m4a other formats works well even flac at 192khz 24 bits on BubbleUpnp but Naim app is seeing them as 16 bits 44khz flac. Also the above m4a track works well în Naim app.