2018 SL/Pixel 2, having this issue. A few different variations:

1. Android Auto will still be running on the phone, but it drops back to the nissan screen on the HU. I have to disconnect/reconnect my phone twice for AA to come back on the HU. Music will automatically begin playing again.
2. AA will go back on the HU, then come back. I can hit play and my music will resume like nothing happened.

I've tried a few different cables, cheap one from monoprice (https://www.monoprice.com/product?p_id=14925) and an Anker Powerline + (https://smile.amazon.com/Anker-PowerLine-Charging-Samsung-MacBook/dp/B071G5WSK2/ref=sr_1_5?ie=UTF8&qid=1528916315&sr=8-5&keywords=anker+usb+c+to+a)

My Pixel 2 worked fine on my previous HU (Sony XAV-AX100)...no disconnecting at all.

I definitely agree with this. While it's one of the HMDs with the least friction with regards to set up, the initial setup can be a beast. A couple of tips:

• Get one of the small power banks and a fairly short USB-C cable that can be used to continually power the HMD for extended play. Have it charged and ready.
• Use the 5Ghz wifi channel if you have it, you won't want to be too far from your router.
• Make sure all your devices (Quest, Phone and Chromecast [if you use one]) are all on the same wifi channel and if using a guest network, make sure guest isolation is disabled (or better yet, add your devices specifically to your router).
• Create/Log in to the Oculus account you'll be using (ideally the one for whom the gift is to be given), perform any device updates, purchase or download any software to the device (and I get updates for apps often).
• Install any demos and/or free apps (definitely First Steps and First Contact) so that will be available on start.
• If you are going to use a Chromecast (or another supported casting device) to show on a TV or projector what the person using the Quest is experiencing, have that set up and tested.
• Make sure fresh AA batteries are in the controllers, charge HMD fully and after all is said and done, shut it down completely --put back in the packaging as neatly as possible.

I know part of the fun might be the setup, but technical glitches can be frustrating when someone is anticipating playing it immediately. Make sure you position it so it's the last gift that is opened, however, or the rest of the gifts may not be opened for a while.