There is an issue with Help Books that started with the release of macOS 14.4. The issue is that when an app attempts to go directly to a Help Book page, the help viewer opens to the Help Book's main index page, rather than the specific page requested. As I investigated the issue I found that the requested page was actually part of help viewer's navigation history, and all I had to do was to click the Back navigation arrow and the requested page would be displayed. So it seems like the requested page is momentarily visited but is then (for whatever reason) quickly replaced by the main index page.
Our app uses the AHGotoPage() API for directly accessing our Help Book's pages. This is the same mechanism/code that our app has used for more than a decade and has never caused us any issues. Everything works fine on macOS 14.3.0 and earlier. I've scoured the documentation and can't find any newer APIs for accessing Help pages. I've also tried various other things (e.g. reworking the code, creating new indexes for the app's Help, etc.), but none of it seems to make a difference. As far as I can tell, the issue seems to stem from some change made to the OS.
So my questions are: Is this a known bug? And if so, is there any ETA on a fix? Is there something different we should be doing for newer versions of the OS (create indexes differently, use a different API, etc.)?