Not Pausing for bt Calls or Nav on Head Unit

[milldrove]

I am having trouble with Poweramp on my card head unit.  It will not pause (or reduce sound level) for telephone calls or navigation instructions although both these options are set to on - there is a brief pause in the music for a second or so; then it  just resumes playing. The unit is an Xtrons Rockchip PX5 box running Android 8.0  - I am also using Car Launcher Pro, but can't see how this could affect it.  May have to find another player app - bummer really as this is probably the best music player I've found.