PO-Matched Invoice Edits for ISP Invoices-Attribute set for Number in entity Invoice Failed

Users experience an error when modifying the Invoice Number of an ISP PO-Based Invoice. 

A workaround does exist at this time. 

Error:

Attribute set for Number in entity Invoice failed

Changing the invoice number in any form causes this error. The only known workaround is to cancel a line item on the invoice (then re-creating a line manually).  This allows the invoice number to be modified. 

Is there a root cause to this error?

PO-Matched Invoice Edits for Supplier Portal Invoices

Feature URL:

Thank you

-Brandon