'Local File' Playback over Bluetooth + Navigation (Google Maps) Notifications

[wbeyer]

Typically when playing Spotify tracks over Bluetooth, the Spotify audio will 'dim' when Google Maps provides navigation notifications over the same Bluetooth connection. However, I've noticed that this only seems to be the case when playing back songs which are on the Spotify service (streaming or downloaded to my Android device). When using a playlist which consists exclusively of 'local files' (i.e. songs not on Spotify, downloaded to my phone via Spotify's playlist feature), the songs continue to play at full volume over navigation notifications, making the notifications basically inaudible.

Has anyone else experienced this behavior? Is there any sort of fix available?