UML24 — UML state machines: inconsistent subset of StateMachine::extendedStatemachine

Issue 15265 proclaimed that StateMachine::extendedStatemachine should subset Classifier::redefinedClassifier. However, while the text entry for this field does this, the diagram in Figure 15.3 subsets Behavior::redefinedBehavior instead. It seems that the fix was not applied properly. Note that Behavior::redefinedBehavior is not a derived union property, so Figure 15.3 is just plain wrong – although it could be argued that the proper fix is to make it a derived union and have StateMachine::extendedStatemachine redefine Behavior::redefinedBehavior

Figure 15.3 (referring to the version of 2.4 published in September 2010) is not wrong – it is valid for a property to subset a non-derived one. However the semantic question here is what exactly extendedStateMachine is supposed to mean that cannot be accomplished by using redefinedBehavior.
It is wrong, however, in the sense that resolution 15265 was not correctly or consistently applied.
At this point we need at least to make the resolution consistent.
I propose to do this by making extendedStateMachine redefine behavior::redefinedBehavior, having the effect that only a state machine may redefine a state machine.