- Add LODGroup component to any gameobject
- Select one of the LOD levels and click on the Add Renderer button
- Close the Window that opens (the one that let's you select a renderer)

Result:
NullReferenceException: Object reference not set to an instance of an object
UnityEditor.LODGroupEditor+<GetRenderers>c__AnonStorey50.<>m__B4 (UnityEngine.GameObject go)
System.Linq.Enumerable+<CreateWhereIterator>c__Iterator1D`1[UnityEngine.GameObject].MoveNext ()
System.Linq.Enumerable.Count[GameObject] (IEnumerable`1 source)
UnityEditor.LODGroupEditor.GetRenderers (IEnumerable`1 selectedGameObjects, Boolean searchChildren)
UnityEditor.LODGroupEditor.HandleAddRenderer (Rect position, IEnumerable`1 alreadyDrawn, Rect drawArea)
UnityEditor.LODGroupEditor.DrawRenderersInfo (Int32 horizontalNumber)
UnityEditor.LODGroupEditor.OnInspectorGUI ()
UnityEditor.InspectorWindow.DrawEditor (UnityEditor.Editor editor, Int32 editorIndex, Boolean forceDirty, System.Boolean& showImportedObjectBarNext, UnityEngine.Rect& importedObjectBarRect, Boolean eyeDropperDirty)
UnityEditor.ContainerWindow:InternalCloseWindow()