I changed it with a different RSHTech 7-port USB hub, and also the black-display screen reboots go on. I am stumped right now, really starting to suspect my UPS of spikes or momentary cutouts. Anyway I feel the Sabrent https://amaanatti295952.blogtov.com/8977709/the-smart-trick-of-adafruit-industries-usb-mini-hub-with-power-switch-that-no-one-is-discussing