P03B2002 / P03B11 - Attention program for inserting invoice in use, or printing from order in progre

Hi, since yesterday we are experiencing an error while entering a credit note in jde.
The user was entering a credit note, after saving in the first screen of the P03B2002 he was taken to the next screen for entering the account.
He came out because he didn't know what account to enter.
At that point the system had detached an invoice number from him but in fact without having created it since the user had exited.
Subsequently the user tried to re-insert the credit note and on the first save he receives the following error.

"Attention program for inserting invoice in use, or printing from order in progress"