Print invoice - incorrect values on second page

Hello,
I have a problem in NAV2017 (BE - CU11) with printing a batch of invoices/CN (customized reports, not 206 or 207).
The problem is that the header information of the second invoice/CN is printed on the last page of the first report. Printing 1 invoice is always correct.
Some report information:
- The header information is printed on the 'page header' using getdata and setdata functions
- The lines are grouped on invoice number + copy. There is a page break after each instance of the group, and at the end.
- In the group header the setdata functions are called in textboxes using the 'visibility' property.
- There is a group footer with a textbox containing a VAT text and/or payment conditions
- The invoice totals are printed on the last page of the invoice in the 'page footer' section using getdata functions. This is done to print the total on the bottom of the page and not just after the detail lines.

If invoice lines are printed on the last page this works fine. However if only the group footer is printed on the last page of the invoice, then this page contains the data of the next invoice (header and footer information). And from then on it goes wrong for every invoice printed later: the header information is the info from the next invoice, but the detail information is correct.

Does anyone know how I could solve this? CU21 has the same problem, so an update is not the solution.
I already tried to print the VAT text as detail line in the tablix, but this doesn't solve it. Neither does creating a new tablix for the 'setdata' functions.

Thx in advance,
Andy