Diagnosis
You are no longer permitted to branch off into the filed documentssince overdue items have already been selected for withholding and thepayment block has thus been set in the corresponding line item. Thepayment block is however only written to the database if you save orpost the outpayment.
If you branch off into the filed documents, you would be able to enteror change and then save documents. By saving the latter, the systemsimultaneously writes the payment block to the database.
If you were to subsequently cancel the outpayment, i.e. you neithersave nor post it, the payment block remains in the document and wouldhave to be deleted manually.