Unity Fabric/Crashytics integration failure

问题

I'm having trouble integrating the Fabric package into my unity project.

After I've imported the latest package version 1.2.8. I can sign in to Fabric, select my organisation and select Crashlytics to be imported. This is where the crash occurs. The Crashlytics package is downloaded and on import completion it either crashes or if i'm lucky freezes on the Fabric window producing these errors:

SynchronizationLockException: Object synchronization method was called from an unsynchronized block of code.
Fabric.Internal.Editor.Update.Dependency.DependencyGraphManager.Continue () (at Assets/Fabric/Editor/Update/Dependency/DependencyGraphManager.cs:44)
Fabric.Internal.Editor.Update.PeriodicUpdateManager.Continue () (at Assets/Fabric/Editor/Update/PeriodicUpdateManager.cs:105)
Fabric.Internal.Editor.Controller.PluginController.CleanKitUpgrade (System.String name) (at Assets/Fabric/Editor/GUI/Controller/PluginController.cs:403)
Fabric.Internal.Editor.Controller.PluginController.PageFromState () (at Assets/Fabric/Editor/GUI/Controller/PluginController.cs:468)
Fabric.Internal.Editor.Editor.OnGUI () (at Assets/Fabric/Editor/GUI/Editor.cs:52)
System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.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:305)
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 /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:313)
System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) (at /Users/builduser/buildslave/mono/build/mcs/class/referencesource/mscorlib/system/reflection/methodbase.cs:229)
UnityEditor.HostView.Invoke (System.String methodName, System.Object obj) (at /Users/builduser/buildslave/unity/build/Editor/Mono/HostView.cs:295)
UnityEditor.HostView.Invoke (System.String methodName) (at /Users/builduser/buildslave/unity/build/Editor/Mono/HostView.cs:288)
UnityEditor.HostView.InvokeOnGUI (UnityEngine.Rect onGUIPosition) (at /Users/builduser/buildslave/unity/build/Editor/Mono/HostView.cs:261)
UnityEditor.DockArea.OldOnGUI () (at /Users/builduser/buildslave/unity/build/Editor/Mono/GUI/DockArea.cs:398)
UnityEngine.Experimental.UIElements.IMGUIContainer.DoOnGUI (UnityEngine.Event evt) (at /Users/builduser/buildslave/unity/build/Runtime/UIElements/Managed/IMGUIContainer.cs:182)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

and

NullReferenceException: Object reference not set to an instance of an object
Fabric.Internal.Editor.Editor.OnGUI () (at Assets/Fabric/Editor/GUI/Editor.cs:54)
System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.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:305)
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 /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:313)
System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) (at /Users/builduser/buildslave/mono/build/mcs/class/referencesource/mscorlib/system/reflection/methodbase.cs:229)
UnityEditor.HostView.Invoke (System.String methodName, System.Object obj) (at /Users/builduser/buildslave/unity/build/Editor/Mono/HostView.cs:295)
UnityEditor.HostView.Invoke (System.String methodName) (at /Users/builduser/buildslave/unity/build/Editor/Mono/HostView.cs:288)
UnityEditor.HostView.InvokeOnGUI (UnityEngine.Rect onGUIPosition) (at /Users/builduser/buildslave/unity/build/Editor/Mono/HostView.cs:261)
UnityEditor.DockArea.OldOnGUI () (at /Users/builduser/buildslave/unity/build/Editor/Mono/GUI/DockArea.cs:398)
UnityEngine.Experimental.UIElements.IMGUIContainer.DoOnGUI (UnityEngine.Event evt) (at /Users/builduser/buildslave/unity/build/Runtime/UIElements/Managed/IMGUIContainer.cs:198)
UnityEngine.Experimental.UIElements.IMGUIContainer.HandleIMGUIEvent (UnityEngine.Event e) (at /Users/builduser/buildslave/unity/build/Runtime/UIElements/Managed/IMGUIContainer.cs:338)
UnityEngine.Experimental.UIElements.IMGUIContainer.DoRepaint (UnityEngine.IStylePainter painter) (at /Users/builduser/buildslave/unity/build/Runtime/UIElements/Managed/IMGUIContainer.cs:69)
UnityEngine.Experimental.UIElements.Panel.PaintSubTree (UnityEngine.Event e, UnityEngine.Experimental.UIElements.VisualElement root, UnityEngine.Matrix4x4 offset, UnityEngine.Rect currentGlobalClip) (at /Users/builduser/buildslave/unity/build/Runtime/UIElements/Managed/Panel.cs:532)
UnityEngine.Experimental.UIElements.Panel.PaintSubTreeChildren (UnityEngine.Event e, UnityEngine.Experimental.UIElements.VisualElement root, UnityEngine.Matrix4x4 offset, UnityEngine.Rect textureClip) (at /Users/builduser/buildslave/unity/build/Runtime/UIElements/Managed/Panel.cs:547)
UnityEngine.Experimental.UIElements.Panel.PaintSubTree (UnityEngine.Event e, UnityEngine.Experimental.UIElements.VisualElement root, UnityEngine.Matrix4x4 offset, UnityEngine.Rect currentGlobalClip) (at /Users/builduser/buildslave/unity/build/Runtime/UIElements/Managed/Panel.cs:536)
UnityEngine.Experimental.UIElements.Panel.Repaint (UnityEngine.Event e) (at /Users/builduser/buildslave/unity/build/Runtime/UIElements/Managed/Panel.cs:564)
UnityEngine.Experimental.UIElements.UIElementsUtility.DoDispatch (UnityEngine.Experimental.UIElements.BaseVisualElementPanel panel) (at /Users/builduser/buildslave/unity/build/Runtime/UIElements/Managed/UIElementsUtility.cs:241)
UnityEngine.Experimental.UIElements.UIElementsUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr) (at /Users/builduser/buildslave/unity/build/Runtime/UIElements/Managed/UIElementsUtility.cs:78)
UnityEngine.GUIUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr) (at /Users/builduser/buildslave/unity/build/Runtime/IMGUI/Managed/GUIUtility.cs:175)

Has anyone else had any issues with Fabric integration and knows how to rectify this issue?

I'm using Unity 2017.4.4f1 with scripting runtime version .Net 4.6