I've never faced this issue with any xperia in my past 5 years of experience. My xperia xz premium when connected to Bluetooth devices while playing songs it works well for sometime and then suddenly the sound starts coming from my phone rather than Bluetooth device which is still connected. I can see the device is still connected but the song sound comes from phone rather than bt device. I then turns off and then on my Bluetooth on xperia and reconnects to solve the issue. And there's no problem with my Sony car audio system and srs xb20 portable speaker,it's surely xperia's fault
