1 Create new project
2 Create cube and select in in Hierarchy
3 Create new animation in AnimationWindow (for the cube):
- press "Add property" and add Transform.Position
- move Cube in scene

Actual result: notice in console few

ArgumentException: GUILayout: Mismatched LayoutGroup.Repaint
UnityEngine.GUILayoutUtility.BeginLayoutGroup (UnityEngine.GUIStyle style, UnityEngine.GUILayoutOption[] options, System.Type LayoutType) (at C:/buildslave/unity/build/artifacts/generated/common/runtime/GUILayoutUtility.gen.cs:210)
UnityEditor.EditorGUILayout.BeginHorizontal (UnityEngine.GUIContent content, UnityEngine.GUIStyle style, UnityEngine.GUILayoutOption[] options) (at C:/buildslave/unity/build/Editor/Mono/EditorGUI.cs:6401)
UnityEditor.EditorGUILayout.BeginHorizontal (UnityEngine.GUILayoutOption[] options) (at C:/buildslave/unity/build/Editor/Mono/EditorGUI.cs:6380)
UnityEditor.EditorGUILayout.LabelField (UnityEngine.GUIContent label, UnityEngine.GUIContent label2, UnityEngine.GUIStyle style, UnityEngine.GUILayoutOption[] options) (at C:/buildslave/unity/build/Editor/Mono/EditorGUI.cs:5129)
UnityEditor.EditorGUILayout.HelpBox (System.String message, MessageType type, Boolean wide) (at C:/buildslave/unity/build/Editor/Mono/EditorGUI.cs:6270)
UnityEditor.AnimatorInspector.OnInspectorGUI () (at C:/buildslave/unity/build/Editor/Mono/Inspector/AnimatorInspector.cs:99)
UnityEditor.InspectorWindow.DrawEditor (UnityEditor.Editor editor, Int32 editorIndex, Boolean forceDirty, System.Boolean& showImportedObjectBarNext, UnityEngine.Rect& importedObjectBarRect, Boolean eyeDropperDirty) (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:1132)
UnityEditor.DockArea:OnGUI()