The redirect after authentication trims the original URL's end fragment

What can be done to consistently navigate both the authenticated and the yet-to-be-authenticated users to the correct URL that contains a page fragment-ID? (scenario below)

When a SharePoint Online user is provided an URL to a PDF document that is stored in a Document Library, and if the link contains a "fragment-id" as follows:

.../file.pdf#page=9

Then the document will directly display for the user, page 9, in the browser.

However if the user is NOT already logged-on to SPO, when the user authenticates through the logon sequence, the user is redirected to the following:

...file.pdf (fragment missing)

And the page fragment in the original URL is missing from the end of the redirect-URL.

Thanks in advance for your solutions