Vendor submitted the invoices for more value than the PO and GR value.
For example GR Value =PO Value = 100 for qty=1.
Vendor Invoice = 120 for qty 1.
On performing MIRO, the invoice is blocked. Vendor is asked to submit the Credit Note.
We observed even without entering the Credit Note user is able to release the blocked invoice.
Blocking of invoices objective is completely of no use then if there is no control. users are releasing invoices with entering credit note.
If there anyway or check where blocked invoices are not released till the credit note is entered or invoices are corrected or correctly submitted by vendor.