Project Status Change, tied to translator Invoice creation?

Hi there,

I have a very simple question, but couldn't find the info on this in the Resources: 

We have at certain times seen, during invoice creation, that invoices for projected already run at an earlier time, came back when running a new set invoices several weeks later.

I feel that this is due to projects who had a project status of "Completed" when invoices were first created, then being put on "Archived" for archival purposes, but when we needed to quickly look up something for that project, we had to return the project to for instance "In progress" or "Completed" status to gain access to the Editor.

Of course, this is undesirable, because translators must not be paid twice for the same work.

What might cause invoices, i.e. work of translators, to be seen again by Wordbee as billable work?

With kind regards,

Ben Pleij,

Textwerk Project Manager.