[Mohawk_1SS]

Thought I'd chime in with a workaround. This happens to me as well, and seems to somehow be tied to the notification settings. It's like the sound is reduced to allow the notification sound to play. I have found if I just turn my phone on silent or vibrate before connecting, the volume is normal.

[adamcars]

Definitely a major glitch. Like clockwork my android auto sound is very low until the map tells me to do something, then the volume is full for the rest of the drive. Rinse and repeat.