I just had the SAME thing happen to me, except it just was black (no video), although my IO indicated that proper signals were being sent. The audio levels and RS-422 control was there, so I almost uninstalled….
HOWEVER, I ended up opening that IO Control Panel thing, and under the ‘CONTROL’ tab, I noticed that the levels were all askew. I hit ‘RESET ALL’ (or whatever it said), and volia, I had my video track back. Evidentely it had dropped the video, contrast, and hue levels to a point where the video was too dark to see.
Try this next time you install the updates (if you get the same issue, of course!)