The Xbox controllers automatically shut off to save the batteries when not in use meaning that if the buttons are not pressed or the sticks are not moved after x amount of time, the controller turns off. I sometimes will watch YouTube or Netflix using the XBSX with the wireless xbox controller and headphones plugged into the comptroller and over and over the Xbox controller shuts off and I have to turn it back on. I now try to periodically move one of the sticks to keep it from shutting off.
I wonder if plugging the Xbox controller into a USB charging cable will help with that. I know it never runs out of battery power keeping it plugged in. I have a phone charger plugged in to an ac outlet. I need to test if it shuts off like that though. I'm not sure. I'll test this the next time I'm watching a video on my XBSX.