Android : Why does ViewPager preserve it's current page even new a instance have been created?

My Context

Assume i have a Fragment contain a ViewPager which have 3 pages(fragment). My onCreateView method:

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.main_tv_fragment, null);
        listFragment = new ArrayList<>();
        listFragment.add(new EventFragment());
        listFragment.add(new ChannelFragment());
        listFragment.add(new FavoriteFragment());
        viewPager = (ViewPager) rootView.findViewById(R.id.viewpager);
        fragmentPagerAdapter = new MainLiveTVtAdapter(
                getChildFragmentManager(), listFragment);

        slidingTabLayout = (SlidingTabLayout) rootView.findViewById(R.id.sliding_tabs);
        // Center the tabs in the layout
        slidingTabLayout.setDistributeEvenly(true);
        slidingTabLayout.setCustomTabColorizer(null);
        try {
            viewPager.setAdapter(fragmentPagerAdapter);
        } catch (Exception ex) {
            ex.getMessage();
        }
        slidingTabLayout.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
            @Override
            public int getIndicatorColor(int position) {
                return getActivity().getResources().getColor(R.color.action_bar_bg);
            }
        });
        slidingTabLayout.setViewPager(viewPager);
        viewPager.setOffscreenPageLimit(5);
        viewPager.setAdapter(fragmentPagerAdapter);
        slidingTabLayout.setViewPager(viewPager);
        viewPager.setCurrentItem(page, false);
        return rootView;
    }

I called viewPager.setCurrentItem(page, false); to set the current page of ViewPager, assume page = 1 mean the second page. When fragment is rendered in window, the second page is shown up, i scroll ViewPager to third page then replace this fragment by another one. After that i recreate this fragment and bring it on, but the ViewPager still shown the third page even viewPager.setCurrentItem(page, false); was called with page = 1.

As you can see above, ViewPager have been created new instance and the Adapter is also.

Can anyone explain why it happen?