Considering following usage of a4j:push I would expected that the bound listener method is invoked each time the push component receives data:
The a4j:ajax behavior itself is called and the "content" component is re-rendered, but the listener method is not invoked.
It does not work for the "subscribed" event, too.
The same a4f:ajax markup works for example inside a commandButton with "action" event:
FYI, this is my dummy listener method for testing purposes: