Alert Hypertext Marker Gives Inconsistent PDF Results

Reading another discussion about using FM's Alert hypertext marker to generate sticky-note comments in PDF output, I was thinking this would be a good addition to my group's toolset, to flow our editorial comments and questions back to authors and other stakeholders. When I tested it, though, I got unexpectedly inconsistent results.

For reference, we use unstructured FM2019 and Acrobat 2017 Pro (within TCS2019) to publish books (i.e., no dynamic/online formats required). I tried inserting an Alert marker in text in a few different files and created PDFs in a few different ways (i.e., print, save as, publish), and I got varying results:

• In one file, the marker turned into not one, but three PDF sticky notes, identical to each other but scattered around the marker location. I tried deleting and reinserting the marker, and tried outputting to PDF in all three ways, but got the same result each time.
• In another file, I got just one sticky when I used save as and publish to generate a PDF, but no sticky at all when I printed to PDF. The sticky I did get wasn't sensibly close to the actual marker location.
• Only in one file did I consistently get a single sticky in the PDF that was usefully near the FM marker location.

All three of the files I used were created from our standard book-chapter template; I can't think of any differences between the files that could account for the differing results. Any idea what I'm missing here?