Upgraded from 8.55 and the app starts fine for me on Q2, regardless of whether tracking is enabled or disabled.
@Yar#1559 The 'drag video' control is really broken in this version. When I press the button combo to activate drag mode, the view jumps (i.e. the virtual camera rotates) without me doing any dragging. If I press and release the button combo several times, without dragging, the view jumps a bit each time and then the video is upside down.