Controller brings up xbox dashboard when i press A

Yes you can still unlock them. To see them bring up the 360 dashboard press start and back at the same time on the xbox one controller. BTW viva piñata wasn't to bad lol

Just do a dashboard refresh. That usually brings it back.

(Hold both triggers and press 'Y' when on the dashboard)

Can you try to refresh the dashboard by following the directions below:

On the Dashboard, press the Guide button, hold RT, then press Y. It should force the dashboard to refresh.

Does that bring up any new content?

Yes, my media remote does bring up the option to turn off the console when the Power On/Home (big Xbox symbol) button is pressed and held.

And just to rule it out as a factor, I am not participating in the dashboard preview program.

I get a completely black screen sometimes on my Xbox One, sometimes while in the Store or browsing my community feed, or even in the middle of a game. Just curious, does anything happen if you press the Home button? I will have a black screen with nothing
at all on it, but in my case, if I press the Home button on my controller, the left side-bar menu will still pop up and I can see that. From there, I'll press Home and it's like the whole Xbox will refresh and the dashboard will load back up again. It's strange
but it does happen to me and I can do that and it will bring the dashboard back. The only bad thing is that if I'm in the middle of a game, I'll lose that and have to start the game over as if I've just quit out of it. Not sure if it's the same issue you're
having, but just thought I would check if anything happens if you press the Home button on your controller when this happens?