In XLSX/PDF the header and footer are repeated in bulk export

Title: In XLSX/PDF the header and footer are repeated in bulk export

Short description: If you in an XLSX template add a header and a footer, and after go to export in XLSX or PDF the header and footer come repeated for each issue you export.

Steps to reproduce:

1. Create a template with a header and a footer.
2. Go to bulk export and choose the previous template

Actual result: The header and footer repeats for each issue.

Expected result: The header and footer should only appear once.

Update

Images and page numbers added to the headers/footers are not exported when exported in quantity.

For example, when exporting only two issues, we see the image and the page numbers entries are present: