not working as expected

I use HTC One (M7) with Android 5.0,
my problem is that while using the phone in car (Skoda, but VW group has all the same), connected via bluetooth, during the phonecall the media output is also going to BT, instead of phone's speaker.
that results in situation when I'm calling with someone, navigation instructions (Waze) is mixing with the call.

The Waze has in own sound settings option to use phone's speaker, but it doesn't work for me. so I tried SoundAbout (trial), set media to phone speaker output, but still the same.
Am I doing something wrong, or SoundAbout is not capable to force media output to phone speaker while call to BT?

Android itself won't allow two different simultaneous audio outputs as you describe. I don't know why. What I had to do, in SoundAbout, is put a setting in the Text-To-Speech section called "Allow during phone call". You can turn this on or off. You would have to be using the SoundAbout TTS wrapper and Waze would have to be using TTS for this to work. Otherwise, the media audio will travel to what ever audio is currently in use. This is why you are hearing Waze during your phone call.

thank you, for advice. unfortunatelly TTS in Waze is not available in my native language. so it seems