Extreme Problems !!!

If there's no picture on the TV screen, try all of the troubleshooting steps listed in this support article: http://support.xbox.com/en-US/xbox-one/console/tv-or-monitor-screen-is-blank-while-connected

Absolute worst case scenario, the console will need to be sent in for repair. See the aforementioned support article for more details.

I have take these things into consideration and it has nothing to do with the position of the sun or the way it would realistically appear with shadows haha. Sometimes the same effect happens when I am struck with an enemy spell the screen will be incredibly
dark for a few moments. Anyway, I spent a long time playing Oblivion when it was first released, also a big game and made by the same developers. No issues there so thats kind of pointless to suggest.

look at where lights are placed if your outside in full daylight in the snow is yoru back to the sun? think of when your acutly outside and your facing toward the sun and some one is coming toward you since there back is to the sun they apear darker due
to the shadow they create facing away form the sun as well as inside if you face a candel your face would be illumated if you turn from the candle your face will be dark but your back would be well lit take thse all in to consideration and if its not that
then as zehq said its a huge game there are bugs some times

Yer happened to me a few times, it's a big game, it's expected.

I play with my brightness turned all the way up. It does get far too dark at times.