Does anyone have a Pixel 2 and an Audi? I have an Audi A4 (B9) and a Pixel 2 and every now and then, the phone asks me if I would like to connect to Audi MMI xxxx. It's almost as if the phone and/or car has forgotten that they've already been paired.
Just an update on this incase anyone else experiences the same issue, it looks like this is down to Android Auto (still early days to say this is definitely the case).
It appears Android Auto connects your device to the car's Bluetooth in the background as all the telephony functions to the car still go over BT and not USB. Therefore it creates a sort of conflict if you've also manually paired your phone via Bluetooth.
I'm guessing the Bluetooth connection created by Android Auto is a "silent" connection, similar to how an Android Wear device connects to your phone. The devices are connected but you wouldn't know it by looking at the Bluetooth icon in the status bar. Before I got into the car this morning I unpaired the Bluetooth connection to the car through the phone's settings but the phone still paired through Bluetooth.