Maybe -> Single causes error (rxjava 2.0.1)

Main.java

package jp.noxi.rx;

import io.reactivex.Single;
import io.reactivex.schedulers.Schedulers;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

public class Main {

    public static void main(String[] args) throws Exception {
        CountDownLatch latch = new CountDownLatch(1);
        Single.just("1")
                .subscribeOn(Schedulers.newThread())
                .filter(it -> Math.random() > 0.5d)
                .flatMapSingle(Single::just)
                .subscribe(
                        it -> System.out.println("success"),
                        it -> {
                            System.out.println("error");
                            it.printStackTrace();
                        });


        latch.await(5L, TimeUnit.SECONDS);
    }


}

stacktrace.txt

java.util.NoSuchElementException
	at io.reactivex.internal.operators.maybe.MaybeFlatMapSingle$FlatMapMaybeObserver.onComplete(MaybeFlatMapSingle.java:104)
	at io.reactivex.internal.operators.maybe.MaybeFilterSingle$FilterMaybeObserver.onSuccess(MaybeFilterSingle.java:92)
	at io.reactivex.internal.operators.single.SingleSubscribeOn$SubscribeOnObserver.onSuccess(SingleSubscribeOn.java:68)
	at io.reactivex.internal.operators.single.SingleJust.subscribeActual(SingleJust.java:30)
	at io.reactivex.Single.subscribe(Single.java:2558)
	at io.reactivex.internal.operators.single.SingleSubscribeOn$SubscribeOnObserver.run(SingleSubscribeOn.java:89)
	at io.reactivex.Scheduler$1.run(Scheduler.java:134)
	at io.reactivex.internal.schedulers.ScheduledRunnable.run(ScheduledRunnable.java:59)
	at io.reactivex.internal.schedulers.ScheduledRunnable.call(ScheduledRunnable.java:51)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)