Well, that is really odd, since I had that article hidden. Perhaps a person could see it if they had URL that I thought was inaccessible. In any case, I took my second piece of advice and made the article a link to the user guide topic. I will investigate what went wrong because I suppose that could be worse! Thank you for alerting us!

Apparently, a previously published but later hidden URL is still indexed and accessible through direct link (bookmark perhaps). I may have to check some other pages. Again, thank you for finding this.