Null Reference exception occurs on adding multiple game objects as child of an empty game object

Steps to Repro:
1. Open attached project > hierarchy window > create > empty game object
2. Select all other game objects > drag them under the newly created empty object

Note:
1. This only occurs after opening the project and moving objects as child
2. Once error is cleared it doesn't occur again

Environment:
Occurring on windows 7

Occurring on:
2018.1.0b9, 2018.1.0b5, 2017.3.0f3, 2017.2.1f1, 2017.1.2p3, 5.6.4p3

Stack Trace:

Error 1:
GUI Error: You are pushing more GUIClips than you are popping. Make sure they are balanced)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

Error 2:
NullReferenceException: Object reference not set to an instance of an object
UnityEditor.IMGUI.Controls.TreeViewController.IsItemDragSelectedOrSelected (UnityEditor.IMGUI.Controls.TreeViewItem item) (at C:/buildslave/unity/build/Editor/Mono/GUI/TreeView/TreeViewController.cs:447)
UnityEditor.IMGUI.Controls.TreeViewController.DoItemGUI (UnityEditor.IMGUI.Controls.TreeViewItem item, Int32 row, Single rowWidth, Boolean hasFocus) (at C:/buildslave/unity/build/Editor/Mono/GUI/TreeView/TreeViewController.cs:461)
UnityEditor.IMGUI.Controls.TreeViewController.IterateVisibleItems (Int32 firstRow, Int32 numVisibleRows, Single rowWidth, Boolean hasFocus) (at C:/buildslave/unity/build/Editor/Mono/GUI/TreeView/TreeViewController.cs:630)
UnityEditor.IMGUI.Controls.TreeViewController.OnGUI (Rect rect, Int32 keyboardControlID) (at C:/buildslave/unity/build/Editor/Mono/GUI/TreeView/TreeViewController.cs:561)
UnityEditor.SceneHierarchyWindow.DoTreeView (Single searchPathHeight) (at C:/buildslave/unity/build/Editor/Mono/SceneHierarchyWindow.cs:583)
UnityEditor.SceneHierarchyWindow.OnGUI () (at C:/buildslave/unity/build/Editor/Mono/SceneHierarchyWindow.cs:409)
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:222)
Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation.
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:232)
System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MethodBase.cs:115)
UnityEditor.HostView.Invoke (System.String methodName, System.Object obj) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:291)
UnityEditor.HostView.Invoke (System.String methodName) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:284)
UnityEditor.HostView.InvokeOnGUI (Rect onGUIPosition) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:251)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)