Contract Project Billing - Able to create invoice with invoice date within a closed period

Summary

Contract Project Billing - Able to create invoice with invoice date within a closed period

Content

Has anyone been able to create a project invoice in Contract Billing using an invoice date that is within a closed period?  I have logged an SR asking about this but have not gotten any information back on it.  I have several invoices that were crated with an invoice date that is within a period that is closed.  When this happens I am not able to transfer the invoice to AR.  I would like to know if the project billing is working as designed.