Performing a factory reset of the lock will reset the master code to Yale default (12345678)
It may not have been completed if this did not happen. (Or the lock may be malfunctioning) I would recommend attempting the reset procedure again to verify. See below from the lock manual.
The following procedure clears the automatic handing of the lock and returns the lock to programming default - deleting all user codes and setting the Master PIN code* back to the default ("12345678"). 1. Remove the batteries and then remove the inside escutcheon to access the reset button. 2. The reset button (see image at right) is located above the PCB cable connector. 3. Hold down the reset button for a minimum of 3 seconds and then reinstall the batteries; once the batteries are properly installed, release the reset button. 4. Reassemble the lock by reversing the same steps on page 6. All features should now be returned to factory default.