Jamie,
Thank you so much for getting back to me. I have followed your suggestions and read the post you recommended.
Here is what I found:
1. By reactivating W3 Total Cache then methodically going down the list of caches turning each off one at a time and re-testing my site in Incognito, I discovered that the Database Cache (Enable database caching to reduce post, page and feed creation time) was causing the error to be displayed.
2. Turning all caches back on, including Minify, but excluding Database, the error message is still gone.
3. However, I have retained the Minify exclusion settings as defined by Yusef in the tangerinemoons.com post and so far it has worked fine. See attached image.
My hunch is that the database caching using the default “Disk” setting could be complicated by the db server being on a different server altogether, but I have not troubleshot further to confirm/deny this possibility.
Again, thank you so much. I’ve documented herein so that others may avoid delays and pain. I love your products!
Best regards,
Mike