Thanks for the help! It appears I have it back up and running! I had already altered it to select the menu item "File-Save", so it no longer showed CMD-S (I do see, now, though, how to check for "Send to" in the future. That could have been the culprit, but then the File-Save wouldn't have suffered from that issue since it was tied directly to Word.
One thing that SEEMS to have been the culprit, though was the macro lived in a "Word Macro Group" folder. That folder is supposed to be active whenever Word is running. But, reading up here: - trigger:Application [Keyboard Maestro Wiki] - I decided to put it in the global folder, and not just the Word folder. Voila! Something about it being nested in the Word folder was making it to where it never fired (even though it used to???)
Is it possible that your "Word" macro group is disabled? Remember that macros can be disabled not just manually but as the result of a Set Macro or Group Enable action in another macro; might you have been experimenting with that action at some point? You could try recreating the macro group from scratch under a new name and then see if the macro runs when it is within that group.