My solution was to recharge the Apple TV remote control. Found out that was the issue after blocking the remote sensor on the front-center of the tv. With it blocked the volume remained the same as set with the manual buttons on the back of the tv. Only when the Apple TV remote control was very near the sensor did the volume skyrocket, without pressing any buttons on the remote control. This occurs once in a while so thinking that it must be the charge state of the remote. Holding the Roku remote (with batteries in it) near the tv did not trigger the volume.
