Payment Batch cannot be Confirmed

Strange error today in Payables, could not confirm Payment Batch. The error message was "APP-SQLAP-10373: To Document Number accounts for more payment documents than those which are in the payment batch. Please re-enter a lower To Document Number." As per Metalink Note 265368.1, this is intended functionality.

I checked the payment batch, it had total 173 payments, out of which only 101 were made OK to pay and rest not selected for payment as they were either below zero or zero. Checked the check numbers in the prelim register and in the account setup. Everything looked okay.

Then started search for the source of the error, first figured out whats the message short name, it is AP_PAY_DOC_NOT_IN_BATCH. Found its not used in any of the PLSQL code. So started grep'ing the AP forms, and found a hit in Payment Workbench APXPAWKB.fmb form. Looked at the form routine TEST_OVERFLOW, this one calls database PLSQL AP_CONFIRM_FORM_PKG.test_overflow_checks. Ran the SQLs in this routines, everything was good. Could not figure out why this error was being thrown.

Finally tried to work around this problem. Navigate to Payment Confirm Window where you see the check numbers From /To and buttons Cancel/Confirm/Restart. Selected Restart option, and this time the Payment Batch was confirmed without any issues.

While I did not find a root cause for this issue, this work-around did work.