This actually IS a bug, only when Stream engine is set to FFMpeg mode and the phone is connected to a Bluetooth device. XiiaLive works fine in FFMpeg mode as long as the phone is not connected to the Bluetooth device.

However, with the same phone and the same Bluetooth device, XiiaLive works as expected if Stream engine is set to Android mode, whether the phone is connected to the Bluetooth device or not.

I'm experiencing this problem with LG G2 on Android KitKat, connected to a Toyota Sienna head unit that supports Bluetooth audio.