-e: see title, the label itself is shown though
--same error thrown on 2017.4, 2018.1.6 and 2018.2b10
--works on Windows same versions

-repro:
--open attached project or make a new one
--select any asset
--in the inspector bottom right add any of the existing labels to it
--NOTICE the label is added and exceptions are being thrown in console

NullReferenceException: Object reference not set to an instance of an object
at UnityEditor.LabelGUI.DrawLabelList (Boolean partiallySelected, Single xMax) [0x00030] in /home/builduser/buildslave/unity/build/Editor/Mono/Inspector/LabelGUI.cs:198
at UnityEditor.LabelGUI.OnLabelGUI (UnityEngine.Object[] assets) [0x00098] in /home/builduser/buildslave/unity/build/Editor/Mono/Inspector/LabelGUI.cs:177
at UnityEditor.InspectorWindow.DrawPreviewAndLabels () [0x00596] in /home/builduser/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:894
at UnityEditor.InspectorWindow.OnGUI () [0x00159] in /home/builduser/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:517
at (wrapper managed-to-native) System.Reflection.MonoMethod:InternalInvoke (object,object[],System.Exception&)
at System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x000d0] in /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.
at System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x000eb] in /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:232
at System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) [0x00000] in /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MethodBase.cs:115
at UnityEditor.HostView.Invoke (System.String methodName, System.Object obj) [0x00013] in /home/builduser/buildslave/unity/build/Editor/Mono/HostView.cs:295
at UnityEditor.HostView.Invoke (System.String methodName) [0x00009] in /home/builduser/buildslave/unity/build/Editor/Mono/HostView.cs:288
at UnityEditor.HostView.InvokeOnGUI (Rect onGUIPosition) [0x00100] in /home/builduser/buildslave/unity/build/Editor/Mono/HostView.cs:255