Audio does not play on Bluetooth if NEMO RESOURCE CLASS OVERRIDE event is set

I set NEMO_RESOURCE_CLASS_OVERRIDE=event for jolla-mediaplayer, but this prevents the audio to be routed to bluetooth.
The audio is played via the speaker (which I can fix by adding route_audio in xpolicy.conf in the group name event, but still no audio plays on the bluetooth earpiece) and setting the audio manually to the bluetooth device results in no audio.
How can I fix this?