Anchors in links confuse the PDF renderer, causes them them open in web browser instead of jumping within the PDF

When exporting a space to PDF, links to pages will correctly jump to the relevant part of the PDF unless the link to the page also has an anchor to a specific part of that page. shaffenden investigated a bit and it seems that the '#' causes the renderer to make the link a full http://blah link, so when it's clicked on it opens in the user's web browser instead of going to that page and anchor within the PDF.