Delivery Date on PDF

[panne003]

Hello,

I have updated my shop to virtuemart 3.6.10. There are many improvement be done with this version. I have one problem.
When i fill in field Date delivery (same as invoice date) de actual delivery date and i save the order header. Thats oke it wil save the data in the backend. But when i print the pdf invoice then the field is not update to the acutual delivery date. The pdf wil not overwrite. In the previous version of virtuemart it did.

What can i change so the pdf will be overwritten when i make a change in the backend invoice. Now i must delete manually the invoice, and then the system will make a new one.