@Wrd2: Does the phone become unresponsive when the screen turns black, or can you return power to the screen by pressing the Power/Side Key? Is the issue occurring when you manually adjust the brightness, and does it happen at a certain level e.g. max brightness? Are you using a certain app or feature at the time?
If you have recently performed a factory data reset, please uninstall any 3rd party apps you may have added following the reset, as this will help to determine if the problem is stemming from an external source.
