Oh, I was assuming you were converting from markdown.
Yes, if you're going from org, it may be a limitation of that.

See https://pandoc.org/org.html on the citation syntax currently
supported.

It may be that we can easily add support for this to org,
but I'm not the one who maintains the org reader, and I'm
also not up on the latest discussions of citations in org...

Joseph Johnson <jj892-eicrhRFjby6OECnbzgFItQ@public.gmane.org> writes:

> Dear all,
>
> Thank you both so much for the replies. I've included a zip file here that
> contains all the necessary files to show the behavior. I tried it both as
> [25] and [p. 25], but the results were identical (this example shows p.
> 25). The file command.txt shows the command I used to produce the docx file
> output.
>
> Could it have something to do with the org-mode conversion? I also noticed
> that the suppress-bibliography option didn't work for me this time, but it
> has in the past.
>
> Many thanks again for your help,
> Joe