Problem Definition

External process pool does not take in space PDF header and footer customizations for table of contents page. Customizations can be picked up when not using external process pool.

      <div style="margin-top: 10.0mm;">
       <h1>Custom Header</h1>
      </div>

      <div style="margin-bottom: 10.0mm;">
      <h1>Custom Footer</h1>
      </div>   

div.toc{
   page:toc;
}  

Workaround

Disable external process pool with system property pdf.export.sandbox.disable, per PDF export in Confluence Data Center.