Portugal Localization : Unable sometimes to finalize imported AR Transactions already billed

Summary:

We have 2 upstream systems in which Customer Invoices are certified, the AR transactions already billed are imported and have the status frozen.
When we submit the program 'Finalize Billing Documents for Portugal', we have sometimes the error
JobRequestId = 45438997
legalEntityId = 300000281782393
List of Incompleted External Billed Transaction

List of Incompleted External Billed Transactions
Transaction Number Document Number
FT 99012001/0072299 null
Please check below GDF Segments for the above Transactions.
1.Hash Control Value
2.Certification Number
3.Hash Value (Encrypted Signature)
4.System Entry Date
5.Invoice Status
6.System Source ID
Delete and re-import the transactions with complete information.
No data found to be processed for the encryption signature generation based on the submitted parameters. (JE-750091)