OnSubscribeCombineLatest#MultiSourceProducer request method get different result?

In request method,there is a line code ‘😮.unsafeSubscribe(s);’ and I find the unsafeSubscribe()'s note is ‘Subscribes to an Observable and invokes {@link OnSubscribe} function without any contract protection,error handling, unsubscribe, or execution hooks.’. This is my code:

Observable<Long> observable1 = Observable.interval(0, 1000, TimeUnit.MILLISECONDS)
                    .map(new Func1<Long, Long>() {
                        @Override
                        public Long call(Long aLong) {
                            return aLong * 5;
                        }
                    }).take(5);
            Observable<Long> observable2 = Observable.interval(500, 1500, TimeUnit.MILLISECONDS)
                    .map(new Func1<Long, Long>() {
                        @Override
                        public Long call(Long aLong) {
                            return aLong * 10;
                        }
                    }).take(4);
            Observable.combineLatest(observable2, observable1, new Func2<Long, Long, Long>() {
                @Override
                public Long call(Long aLong, Long aLong2) {
                    Log.i("ppppp", "combineLatest aLong = " + aLong + "   aLong2 =" + aLong2);
                    return aLong + aLong2;
                }
            }).subscribe(new Subscriber<Long>() {
                @Override
                public void onCompleted() {
                    System.out.println("Sequence complete.");
                }
                @Override
                public void onError(Throwable e) {
                    System.err.println("Error: " + e.getMessage());
                }
                @Override
                public void onNext(Long aLong) {
                    System.out.println("combineLatest Next: " + aLong);
                }
            });

I run this code and get two different results. (1) Next: 0 Next: 5 Next: 10 Next: 20 Next: 25 Next: 35 Next: 40 Next: 50 (2) Next: 0 Next: 5 Next: 15 Next: 20 Next: 25 Next: 35 Next: 40 Next: 50

[akarnokd]

If you have a full row, that is the first time the combiner function is called.

PublishSubject<String> a = PublishSubject.create();
PublishSubject<String> b = PublishSubject.create();
PublishSubject<String> c = PublishSubject.create();

Observable.combineLatest(a, b, c, (u, v, w) -> u + v + w).subscribe(System.out::println);

a.onNext("1");
b.onNext("1");
a.onNext("2");
b.onNext("2");
b.onNext("3");
System.out.println("Full row:");
c.onNext("1");

It will print

Full row:
231

[akarnokd]

It was readable.