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Or rather the FragmentStateAdapter holds a reference to the ViewPager2 instance.

Here is a workaround When using ViewPager2 inside a Fragment.

Use the FragmentStateAdapter (FragmentManager, Lifecycle) constructor instead of the FragmentStateAdapter(Fragment) one and pass the view lifecycle as argument.

FragmentManager fm = getChildFragmentManager();
Lifecycle lifecycle = getViewLifecycleOwner().getLifecycle();
fragmentAdapter = new FragmentAdapter(fm, lifecycle);

#3 This works, thank you!

Also seeing a situation where the FragmentLifecycleCallbacks registered here is never unregistered:

private void scheduleViewAttach(final Fragment fragment, @NonNull final FrameLayout container) { // After a config change, Fragments that were in FragmentManager will be recreated. Since // ViewHolder container ids are dynamically generated, we opted to manually handle // attaching Fragment views to containers. For consistency, we use the same mechanism for // all Fragment views. mFragmentManager.registerFragmentLifecycleCallbacks( new FragmentManager.FragmentLifecycleCallbacks() { // TODO(b/141956012): Suppressed during upgrade to AGP 3.6. @SuppressWarnings("ReferenceEquality") @Override public void onFragmentViewCreated(@NonNull FragmentManager fm, @NonNull Fragment f, @NonNull View v, @Nullable Bundle savedInstanceState) { if (f == fragment) { fm.unregisterFragmentLifecycleCallbacks(this); addViewToContainer(v, container); } } }, false); }

Pardon the formatting in the last comment:

private void scheduleViewAttach(final Fragment fragment, @NonNull final FrameLayout container) {
        // After a config change, Fragments that were in FragmentManager will be recreated. Since
        // ViewHolder container ids are dynamically generated, we opted to manually handle
        // attaching Fragment views to containers. For consistency, we use the same mechanism for
        // all Fragment views.
        mFragmentManager.registerFragmentLifecycleCallbacks(
                new FragmentManager.FragmentLifecycleCallbacks() {
                    // TODO(b/141956012): Suppressed during upgrade to AGP 3.6.
                    @SuppressWarnings("ReferenceEquality")
                    @Override
                    public void onFragmentViewCreated(@NonNull FragmentManager fm,
                            @NonNull Fragment f, @NonNull View v,
                            @Nullable Bundle savedInstanceState) {
                        if (f == fragment) {
                            fm.unregisterFragmentLifecycleCallbacks(this);
                            addViewToContainer(v, container);
                        }
                    }
                }, false);
    }

Same problem. It creates new fragments instead of reattaching to the existing one that's displayed.

Re comment#18, we still support the widget, but we're really short-handed, so only able to do the bare minimum. I think the next step for us will be to release a newer stable version for people to benefit from latest versions of dependencies.

Looking at this issue, it looks like workaround were shared in early comments; while not ideal, still allowing the widget to be used. Ideally we'd be able to fix all issues like this, so workaround wouldn't be needed.

We stopped using viewpagers in all of our apps as a direct result of this bug, and since there is no priority in fixing it for more than 3 years we also don't plan on using it ever again.