Incorrect generation of inheritance relationship from yang file

When this construction:
leaf sub-type {
type identityref

{ base openflow-action:experimenter; }

}
is placed into 'module', 'container', 'grouping', 'augment' node,
yangtools generate incorrect hierarchy between abstract classes.

Example:
Here is hierarchy described placed in yang file:

identity action-base

{ description "Base identity for action types"; }

identity experimenter

{ description ""; base action-base; }

leaf sub-type {
type identityref

{ base experimenter; }

}

Therefore correct inheritance relationship should be: 'Experimenter extends ActionBase'.
But generated code is as follows: 'Experimenter extends BaseIdentity'
(Generated abstract class (Experimenter.java) looses it's parent class (ActionBase.java))
If you comment this part of yang file:
"leaf sub-type {
type identityref

{ base openflow-action:experimenter; }

}"
, suddenly generation of inheritance works properly.

Yang file is attached in attachment.