When calling a super.methodXXX() on an entity that uses the base class's method to populate a many-to-one bi-directional relationship with "this" scope... you get an org.hibernate.NonUniqueObjectException.
To recreate this issue, run the attached test case. You will see that it runs and dumps a "book" entity. Then go into the book entity an un-comment the setDefaultAuthor() method that calls super.setDefaultAuthor()
More information on the genesis of this error can be found here: https://groups.google.com/d/topic/railo/7-VfotlxvFY/discussion