Check the wide settings as that can stretch the screen width (zoom modes / auto wide / 16:9 /14:9 /4:3) so that part of the picture is outwith the visible screen. Generally it should be best to set it at 16:9 so as to avoid picture distortion.
All TVs usually overscan a little but the programme channels should work to a safe area for captions and suchlike - the shopping channels especially would not want to have info off the visible screen.