Screen brightness keeps dimming randomly on xbox one

I switched HDMI ports and it's working fine now. Thank you!

You are welcome, my friend!

Have a nice week and great gaming!

Hello, TheWorm501. Thanks for reaching out. I'm Lucas, an Independent Advisor and a Microsoft user just like you. I'll be glad to help you out.

Would you please try physically resetting your display options?

If there's a disc in the console, eject it.

On the console, press and hold the Xbox button for 10 seconds to turn off the console. Unplug all cables from it, wait for 5 minutes and plug again.

Then, press and hold the Xbox button and the Eject button until you hear a beep to turn on the console. You’ll hear one beep right away and a second beep 10 seconds later. The power light will flash on before the second beep. Don’t let go until you hear the second beep or see the console start up in low resolution mode (the Xbox startup screen will appear slightly pixelated).

In either case, this will start up your console in low resolution mode (640 × 480). To change this setting, press the Xbox button to open the guide. Go to Profile & system > Settings > General > TV & display options, and then select the resolution you want from the Display dropdown.

See if this display reset can improve things for you.

If the issue persists, please try to use a different HDMI cable and plug it on another HDMI port on your TV.

If this also does not work, please try to test your console on another TV if possible.

Feel free to ask back any question and let me know how it goes.

Seems to change based on the light in the room. Kinda like when your phone screen dims. Dark room = dim Xbox logos on the system, Kinect and controller, bright room = bright light.

Some of my friends "dimmed" the screen also as they thought it was too bright.