[AppBarLayout] HeaderScrollingViewBehavior issue

Nobody has claimed this yet.

here's the crash log i received on crashlytics

`Fatal Exception: java.lang.NullPointerException: Attempt to write to field 'boolean android.animation.AnimatorSet$Node.mEnded' on a null object reference
at android.animation.AnimatorSet.onChildAnimatorEnded(AnimatorSet.java:799)
at android.animation.AnimatorSet.start(AnimatorSet.java:640)
at android.animation.StateListAnimator.start(StateListAnimator.java:188)
at android.animation.StateListAnimator.setState(StateListAnimator.java:181)
at android.view.View.drawableStateChanged(View.java:18049)
at android.view.ViewGroup.drawableStateChanged(ViewGroup.java:6479)
at android.view.View.refreshDrawableState(View.java:18108)
at android.view.View.dispatchAttachedToWindow(View.java:15589)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2955)
at android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:2962)
at android.view.ViewGroup.addViewInner(ViewGroup.java:4510)
at android.view.ViewGroup.addView(ViewGroup.java:4312)
at android.view.ViewGroup.addView(ViewGroup.java:4252)
at android.view.ViewGroup.addView(ViewGroup.java:4225)
at androidx.viewpager2.adapter.FragmentStateAdapter.addViewToContainer(FragmentStateAdapter.java:406)
at androidx.viewpager2.adapter.FragmentStateAdapter.placeFragmentInViewHolder(FragmentStateAdapter.java:328)
at androidx.viewpager2.adapter.FragmentStateAdapter.onViewAttachedToWindow(FragmentStateAdapter.java:273)
at androidx.viewpager2.adapter.FragmentStateAdapter.onViewAttachedToWindow(FragmentStateAdapter.java:73)
at androidx.recyclerview.widget.RecyclerView.dispatchChildAttached(RecyclerView.java:8377)
at androidx.recyclerview.widget.RecyclerView$5.addView(RecyclerView.java:954)
at androidx.recyclerview.widget.ChildHelper.addView(ChildHelper.java:131)
at androidx.recyclerview.widget.RecyclerView$LayoutManager.addViewInt(RecyclerView.java:9430)
at androidx.recyclerview.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:9388)
at androidx.recyclerview.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:9375)
at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1676)
at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1622)
at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:687)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4645)
at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:4348)
at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4919)
at android.view.View.layout(View.java:17702)
at android.view.ViewGroup.layout(ViewGroup.java:5631)
at androidx.viewpager2.widget.ViewPager2.onLayout(ViewPager2.java:535)
at android.view.View.layout(View.java:17702)
at android.view.ViewGroup.layout(ViewGroup.java:5631)
at com.google.android.material.appbar.HeaderScrollingViewBehavior.layoutChild(HeaderScrollingViewBehavior.java:149)
at com.google.android.material.appbar.ViewOffsetBehavior.onLayoutChild(ViewOffsetBehavior.java:43)
at androidx.coordinatorlayout.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:953)
at android.view.View.layout(View.java:17702)
at android.view.ViewGroup.layout(ViewGroup.java:5631)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:325)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17702)
at android.view.ViewGroup.layout(ViewGroup.java:5631)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1762)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1606)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1515)
at android.view.View.layout(View.java:17702)
at android.view.ViewGroup.layout(ViewGroup.java:5631)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:325)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17702)
at android.view.ViewGroup.layout(ViewGroup.java:5631)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1762)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1606)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1515)
at android.view.View.layout(View.java:17702)
at android.view.ViewGroup.layout(ViewGroup.java:5631)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:325)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:774)
at android.view.View.layout(View.java:17702)
at android.view.ViewGroup.layout(ViewGroup.java:5631)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2519)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2234)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1372)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6774)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:926)
at android.view.Choreographer.doCallbacks(Choreographer.java:735)
at android.view.Choreographer.doFrame(Choreographer.java:667)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:912)
at android.os.Handler.handleCallback(Handler.java:761)
at android.os.Handler.dispatchMessage(Handler.java:98)
at android.os.Looper.loop(Looper.java:156)
at android.app.ActivityThread.main(ActivityThread.java:6517)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:942)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:832)`

Start by tracing the reported stack from HeaderScrollingViewBehavior.layoutChild through ViewPager2 and FragmentStateAdapter attachment into Android's AnimatorSet. Reproduce the crash if possible and determine the relevant Material Components behavior; done means the crash is prevented and the scenario has regression coverage.

Written by the indexing model from the issue text.