isDone() method doesn't return true after cancel() call on EJB asynchronous method

Method isDone() does not return true after call of cancel method() on Future object bound to call of EJB asynchronous method.
Please check my test:
https://github.com/ochaloup/jboss-as/blob/JBQA-5271-tests-async-pull/testsuite/integration/basic/src/test/java/org/jboss/as/test/integration/ejb/async/AsyncMethodTestCase.java#L196

It's against documentation of cancel method (http://docs.oracle.com/javase/6/docs/api/java/util/concurrent/Future.html#cancel%28boolean%29) where is said:
"After this method returns, subsequent calls to isDone() will always return true. Subsequent calls to isCancelled() will always return true if this method returned true."