That doesn't have anything to do with ZotFile — ZotFile doesn't extract annotations anymore.

But it sounds like the annotation's page label is set to 6 here, and it's page 22 of the actual PDF. The link (22) should take you back to the PDF page where you added the annotation.

If you're seeing something different, can you say more?

I'm not sure what you mean here. If you're clicking a link with page=22, it's going to go to take you to the 22nd page of the PDF. "p. 6" is just text in the citation.

No, I still don’t know what you mean. Can you provide a link to a PDF — or email it to support@zotero.org with a link to this thread — and provide the exact steps in Zotero to reproduce the problem you’re describing?

@dstillman: I think the issue arises on macOS with an external PDF viewer which is called using AppleScript in Zotero's openToPage code. If you click zotero://open-pdf/library/items/5RTYM25B?page=22 to open the "physical" page 22 which corresponds to the "logical" page 1, Zotero calls page 22 but PDF Expert expects page 1.

It seems that there's a workaround for Acrobat (here) and Preview (here), which provide a "Use logical page numbers" option that can be switched off. But this might not be possible in PDF Expert.

A solution could be to replace this code with something like the following:
_openWithPDFExpert: async function (appPath, filePath, page) {
await Zotero.Utilities.Internal.exec('/usr/bin/open', ['-a', appPath, filePath]);
let pageNumber;
// New Boolean preference to call viewer with logical page numbers
if (Zotero.Prefs.get('useLogicalPageNumbersInExternalViewer')) {
pageNumber = Zotero.getLogicalPageNumber(page);
} else {
pageNumber = page;
}
// Go to page using AppleScript (same as Preview)
let args = [
'-e', `tell app "${appPath}" to activate`,
'-e', 'tell app "System Events" to keystroke "g" using {option down, command down}',
'-e', `tell app "System Events" to keystroke "${pageNumber}"`,
'-e', 'tell app "System Events" to keystroke return'
];
await Zotero.Utilities.Internal.exec('/usr/bin/osascript', args);
},

The function getLogicalPageNumber should check whether page labels are defined in the PDF file itself or in Zotero's PDF reader. This modification could also be applied to the Acrobat and Preview handlers on macOS.

(Note that "page" in the PDF specification always refers to the "physical" page. You can define a "dictionary" that maps "page" to a "page label", which is sometimes referred to as a "logical" page. In principle, you could have multiple pages with the same page label, but in normal usage that's not the case.)