It was only bad field setting
If invoice number then invoice date is required
More clearly
Merge branch 'develop' into feature/add-field-with-invoice-date-to-bulkedit
fix flake8
fix tests but now there is no test for invoice_date
clear
create common config generator
Added 2 spaces around +
Merge pull request #105 from kula1922/feature/add-field-with-invoice-date-to-bulkedit

It was only bad field setting