It turns out that I just should have been more patient.
After doing three shutdown-start ups and a few Restarts yesterday in an effort to somehow trigger Windows update (or un-grey the Check for Update button), waiting until another day (today) and trying some shutdown-startups and Restarts today, I wrote this discussion item.
This afternoon, trying again to do a shutdown-startup one more time, Windows update had decided to do the OS update, as well as the other pending updates. I waited until the OS update was finished to confirm that it worked, as checked by channel after the update. It is on the latest build on the beta channel. Updated!
The only thing that was interesting is that the OS update started by itself, I did not need to select it from Windows Update. If I'm not that one only with this behavior, emails in future might mention that "There may be a lag in between the channel change and the OS update with some unusual status behavior in Windows Update until the next OS update is installed." Or something to that effect. Otherwise the channel change worked as advertised. Cheers!
