Marking an Epic as closed returns exception: Cannot read property 'notDone' of undefined

Instance with Atlassian GreenHopper - 6.1.3.3 returns the exception: Uncaught

TypeError: Cannot read property 'notDone' of undefined

This behaviour occurs when users 'Mark an Done' for the Epic in GreenHopper.

Javascript resource is also generated with the exception. No duplicate fields configurations are present for the the Epic fields.