Mitsubishi WS-65613 Aspect Ratio Changing From 4:3 To 9:16 and Zoom

I have a Mitsubishi WS-65613 and the Aspect Ratio will all of a sudden change from 4:3 to 9:16 and Zoom and back again. This is an intermittent problem but its happening more frequently and its starting to drive me nuts. This happened’s when I’m watching TV with my cable box, DVD and Xbox as a source so that leads me to believe it’s the TV that has the problem. I know it’s not the remote’s that is causing this because I have removed them from the equation. Any help would be much appreciated.