Removing the Articulation Body Component from a Gameobject which is attached as a Reference Articulation Object to a Regular Joint during Play mode leads to Null Reference Exceptions in the console.
Refer to the attached Video.

Steps to Reproduce:
1. Open Attached Project
2. Open 'Repro' Scene
3. Enter Play Mode
4. Cube\Capsule > Inspector > Articulation Body > Remove Component

Actual Result:
Null Reference Exception displayed in console

Expected Result:
No errors displayed in console

Note:
The Feature to Connect Articulation bodies to Regular Joints was introduced in 2020.2.0a15

Reproducible with:
2020.2.0a15

Environment:
Windows 10 only

---------------------Stack Trace-------------------------

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.ArticulationBodyEditor.OnSceneGUI () (at <feb76e495af340bfbdc89fc2ad1b8ae4>:0)
System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at <fb001e01371b4adca20013e0ac763896>:0)
Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation.
System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at <fb001e01371b4adca20013e0ac763896>:0)
System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) (at <fb001e01371b4adca20013e0ac763896>:0)
UnityEditor.SceneView.CallOnSceneGUI () (at <feb76e495af340bfbdc89fc2ad1b8ae4>:0)
UnityEditor.SceneView.HandleSelectionAndOnSceneGUI () (at <feb76e495af340bfbdc89fc2ad1b8ae4>:0)
UnityEditor.SceneView.OnGUI () (at <feb76e495af340bfbdc89fc2ad1b8ae4>:0)
UnityEditor.HostView.InvokeOnGUI (UnityEngine.Rect onGUIPosition, UnityEngine.Rect viewRect) (at <feb76e495af340bfbdc89fc2ad1b8ae4>:0)
UnityEditor.DockArea.DrawView (UnityEngine.Rect viewRect, UnityEngine.Rect dockAreaRect) (at <feb76e495af340bfbdc89fc2ad1b8ae4>:0)
UnityEditor.DockArea.OldOnGUI () (at <feb76e495af340bfbdc89fc2ad1b8ae4>:0)
UnityEngine.UIElements.IMGUIContainer.DoOnGUI (UnityEngine.Event evt, UnityEngine.Matrix4x4 parentTransform, UnityEngine.Rect clippingRect, System.Boolean isComputingLayout, UnityEngine.Rect layoutSize, System.Action onGUIHandler, System.Boolean canAffectFocus) (at <b30069c4c77445eb8c5154ce0b24141e>:0)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)

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License type: Pro