I can imagine for existing devices v12 is a huge upgrade, which could
result in some issues that can be fixed by reset. I doubt this works for
a brand new HD that comes with v12. It did do a small update on first
startup.
I have this also with a new Chromecast HD. I have ethernet adapter
connected via usb hub (yes, with enough power). It randomly disconnects
and shows "no internet connection". On wifi this does not occur, its
stable. I have tried several combinations ...