All right. I still don’t what triggered those pesky new post (but not new) notifications (my research shows that I had the private/publish settings correct and the type of maintenance I was doing shouldn’t have triggered it anyway but that’s beside the point) however, I do have a theory and a solution (thanks to the JetPack and WordFence plugins for doing their job).
Because the work I was doing shouldn’t have triggered any notifications but did so anyway (which I think was caused by a combination of things going on this past couple of days), when I perform any type of maintenance, big or small, I’ll be taking my site offline using the Under Construction plugin.
None of the “under construction” plugins specifically stated that subscribers and users will not be affected by any updates, but since they do say it takes my site completely offline, I’m thinking this includes any notifications since the site isn’t live. It is probably overkill for some light maintenance but I’m not taking that chance again.
I’m confident this will help end these kinds of issues in the future.
And, again, thank you for your patience and understanding!