Automatic Sales invoice number not working

When cloning invoices I’ve noticed this week that the invoice numbers are cloning also and not automatically changing with each new invoice like it was before, So at the moment i need to manually change the invoice number on each invoice or re click the automatic invoice box every invoice. How do i change back to automatic allocation of invoice numbers thanks

This is already a bug report: Receipts and Payments clone bug.

You have already identified the only workaround.