Trouble to account invoice with asociated Purchase Order when applied prepayment with asociated the

Hello

I have a prepayment (P1) where has associated a Purchase Order (OC001). This prepayment was validated, posted, and paid. It didn’t generate errors on the prepayment. Well, now I create an invoice (I1) where has associated the same purchase order (OC001), the functional user when tries to validate invoice, generate error QTY Received. The functional user released holds manually and applied the prepayment (P1, remmember that this prepayment has associated purchase order (OC001)) and finally invoice was validated, but when he tries to post (account) the invoice, didn’t create accounting.

My question is how can post invoice if the purchase order associated is both in the prepayment and invoice? How can correct it?