Can't overwrite the print page size from a custom PDF template

Follow this steps to reproduce:

• Create a new wiki page using the "PDF Template" page type
• Save and edit with the object editor
• Set the print page size from the SSX object and save

  @media print {
    @page {
      size: 11.7in 8.3in;
    }
    ...
  

• Register the new PDF template in the wiki administration
• Export an existing wiki page to PDF using the new (custom) PDF template

Expected results: the print page size is the one specified in the custom PDF template
Actual results: the print page size is still the one specified in the PDF sheet (that holds default styles shared by all PDF templates).