Unwanted update event got when use WriteTransaction.put method if createMissingParents is ture.

yang model is:
container cats {
config true;
list cat {
key "id";
uses cat-struct;
list baby

{ key "id"; uses cat-struct; }

}
}
rpc add-baby {
input {
leaf parent

{ type string; }

uses cat-struct;
}
}

Register a same listener to listen cat and baby's changes.Scope is BASE.
If WriteTransaction.put method's createMissingParents argument is false when add-baby, everything seems ok. The listener will only get one event, which is baby created.
But if createMissingParents is true, the listener will get a cat update event, even if the parent cat node already exsits.
Version is Helium-SR2.