So just like many, I was having some issue with Google assistant not registering my voice or not coming up with my voice command. So when I tried to test Android Auto I also noticed even pressing the car button to prompt assistant I got a notice from Google maps saying you need to disable Medium Power Save mode.
Long and behold, I disabled power saving mode and now Google assistant comes up at my voice commands. It seems that saving mode restrict some background tasks that is required by assistant. This used to work fine on Android P, make sure to report this change issue to Samsung.
