Akka Streams takeWhile processing elements even after condition fails

EDIT: I think this may be a bug, so i have reported this as a bug as well.

I have a very simple actor that just prints the number :-

public class PrintLineActor extends AbstractLoggingActor {

  @Override
  public Receive createReceive() {
    return receiveBuilder()
        .match(Integer.class, i -> {
          System.out.println("Processing: " + i);
          sender().tell(i, self());
        }).build();
  }
}

Now, I have a stream to print the even numbers until I encounter an odd element:-

@Test
public void streamsTest() throws Exception {

ActorSystem system = ActorSystem.create("testSystem");
ActorRef printActor = system.actorOf(Props.create(PrintLineActor.class));

Integer[] intArray = new Integer[]{2,4,6,8,9,10,12};
CompletionStage<List<Integer>> result = Source.from(Arrays.asList(intArray))
    .ask(1, printActor, Integer.class, Timeout.apply(10, TimeUnit.SECONDS))
    .takeWhile(i -> i != 9)
    .runWith(Sink.seq(), ActorMaterializer.create(system));

List<Integer> result1 = result.toCompletableFuture().get();
System.out.println("Result :- ");
result1.forEach(System.out::println);

}

I do NOT expect any element after 9 being processed aka being sent to actor. However, I see the number “10” also being processed by actor (but not 12) as seen in below output

Processing: 2
Processing: 4
Processing: 6
Processing: 8
Processing: 9
Processing: 10 //WHY IS THIS BEING PROCESSED BY ACTOR??

Result :- 
2
4
6
8
Why is 10 being processed by actor? How to stop this?

I have tried adding delays and debugging by recording timestamp of events, just to see if 10 is being processed before 9 actually completes, but no, 10 is taken after 9 is processed fully. here are the logs :-

Before Ask: 2 in 1596035906509
Processing inside Actor: 2 at 1596035906509
Inside TakeWhile 2 at  in 1596035906509

Before Ask: 4 in 1596035906609
Processing inside Actor: 4 at 1596035906610
Inside TakeWhile 4 at  in 1596035906610

Before Ask: 6 in 1596035906712
Processing inside Actor: 6 at 1596035906712
Inside TakeWhile 6 at  in 1596035906712

Before Ask: 8 in 1596035906814
Processing inside Actor: 8 at 1596035906814
Inside TakeWhile 8 at  in 1596035906815

Before Ask: 9 in 1596035906915
Processing inside Actor: 9 at 1596035906915
Inside TakeWhile 9 at  in 1596035906916

Before Ask: 10 in 1596035907017 //so 10 is taken much after the 9 is processed fully
Processing inside Actor: 10 at 1596035907017

Result :- 
2
4
6
8

Also, if i replace the .ask with a direct .map(print…), then 10 does not get printed. So why this happens when actor.ask is involved is very strange to me.

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