Been pulling my hair out trying to find the reason for this!

Sales Orders, Duplicate Invoices generate to PDF OK, everything as it should be.

However , Invoices all generate to PDF without header and footer. If changed to HTML output it works OK - headers / footers present.

I'm using Odoo 10 Enterprise, wkhtmltopdf 0.12.1 (with qt fix)

Invoice templates are default - nothing has been modified.