Using ORB and org-noter on PDFs of book chapters

@Adela

I have a feeling that your Org-noter is doing what it is designed to do.

See this part of its README on GitHub.

In a document
Run M-x org-noter when viewing a document (eg. PDF, epub…).
This will try to find the respective notes file automatically. It will search in all parent folders and some specific folders set by you. See org-noter-default-notes-file-names and org-noter-notes-search-path for more information [my emphasis]

If you “associate” an org file with a PDF document with using the :note-document: property within the org file, you would need to start org-noter in it, not in the PDF document.