The three-way match compares the purchase order, goods receipt and supplier invoice. A quantity variance means that the invoice claims more than the received quantity supports. A price variance means that the amount differs from the PO price for the invoiced quantity. Those problems need different evidence and different corrections.
Don't remove a payment block simply to make the status look complete. Receive a missing physical delivery only when the task supplies delivery evidence, then recheck the invoice. The training client allows release after the quantity evidence supports the invoice. A manual block on an unrelated expense invoice remains a separate review. In these tasks you resolve supported quantity shortages and confirm the invoice's payment status.