R12.1.3 Purchasing: Workflow errors after editing requisition with approver completing checkout

While this affects R12.1.3, it also is encountered in R12.2.3 so "ORA-06512 In Workflow When Using Edit Requisition And Approver Completes Checkout" on My Oracle Support from document ID 1969203.1 is quite new and there are patches for both versions which you should check out to make sure you can resolve an issue which I have seen several times in our own R12.1.3 instance!