Page numbering does not work for sandboxed PDF space exports

Trying to apply the page numbering customisations mentioned in the KB article will not work for DC instances that use the external process pool (sandbox) to export PDFs.

Specifically:

@page{    
  @bottom-center{        
  content: "Page " counter(page) " of " counter(pages);        
  font-family: ConfluenceInstalledFont, Helvetica, Arial, sans-  serif;        
  font-size: 8pt;    
  }
}
 
or
 
<span id="pageNum"/>
#pageNum:before { 
content: counter(page); 
}

Server customers and DC customers who have it disabled are not affected.

How to Reproduce

1) Apply any of the above recommendations to add page numbering to PDF exports
2) Export a space as PDF

Workarounds

None at the moment.