Looks like I spoke too soon. Again my main Alexa Show 10" screen started doing the "I don't know how to do that" response like before. This time, only one of the 10 devices did this, while still operating the ISY Portal devices just fine. All others answered "OK".
A power cycle of this device seems to have cleared up this outstanding problem unit, for now.
However, my "TV Lights" commands, I have been using for over three years now, will not function anymore on any unit now.
Thanks amazon....NOT!