Unable to turn off navigation audio

Starting immediately after receipt of version 6.1.3 (3541), acknowledged to be a Beta release, all route navigation voices turn by turn instructions. Audio muted on ABRP screen on Android Auto display in vehicle. Voice navigation turned off in settings in the ABRP phone app. Turning volume completely down when voice prompts played in vehicle silences that single prompt, but the next turn is played at unchanged volume. Phone rebooted. Vehicle navigation system rebooted. Still, this action persists. I understand that I am a beta tester. I am reporting a bug. Please do not tell me to just use the main release version.