App Engine EX_BD_DEL No Success affecting all historical data?

We have run into an unexpected issue on our PeopleSoft FSCM 9.2 (Image 51) system. At around 4 yesterday, a user ran EX_BD_DEL twice, to delete 2 expense reports that had already been budget checked. The first instance completed successfully after 2 minutes and processed 1 document. The second instance failed with No Success and took much longer, showing the following error in the log:

Return: 936 - ORA-00936: missing expression

Failed SQL stmt: UPDATE PS_EX_SHEET_HDR SET BUDGET_HDR_STATUS = 'N', PROCESS_INSTANCE = 11490578 WHERE AND NOT EXISTS ( SELECT 'X' FROM PS_KK_SHDR_EXSHEET KKSH WHERE KKSH.KK_PROC_INSTANCE = 11490578 AND KKSH.KK_SOURCE_TRAN = 'EX_EXSHEET' AND PS_EX_SHEET_HDR.SHEET_ID = KKSH.SHEET_ID )