AP_MATCH Unique constraint error on PO_LINE_MATCHED

Hi,

We are having frequent issues with AP_MATCH process where it gets abended as below. It sounds like usually scenario when a match exception is overriden. Is there a specific business process to be followed for exception override to avoid this issue?

Number of vouchers that were Auto Matched - 0 (7500,403)

Number of vouchers that were Matched with Override - 1 (7500,404)

Number of vouchers that were Matched with Debit Memo - 0 (7500,405)

Number of vouchers that are in Exceptions - 0 (7500,406)

File: /vob/peopletools/src/psappeng/aedebug.hSQL error. Stmt #: 1723 Error Position: 0 Return: 805 - ORA-00001: unique constraint (SYSADM.PS_PO_LINE_MATCHED) violated