Exception in WP-Project after update to 1.3.1 (VS2013 Update2)

Hi all

I am on the way to update my project to 1.3.1 and have done the work according to the update-description.

After that, I have cleaned and rebuild all projects.
I now have a main-problem with the master-detail-page (don’t work like before) and a hard exception in the WP-Project (before the master-detail-page is showed).
I am able to debug the iOS and Android-app on the devices.

As soon as I try to debug the WP-app on the device, it crashes with:

+       Exception   {System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values.
   at Xamarin.Forms.Platform.WinPhone.FontExtensions.ApplyFont(TextBlock self, Font font)
   at Xamarin.Forms.Platform.WinPhone.LabelRenderer.UpdateFont(TextBlock textBlock)
   at Xamarin.Forms.Platform.WinPhone.LabelRenderer.OnElementChanged(ElementChangedEventArgs`1 e)
   at Xamarin.Forms.Platform.WinPhone.VisualElementRenderer`2.SetElement(VisualElement element)
   at Xamarin.Forms.Platform.WinPhone.RendererFactory.GetRenderer(VisualElement view)
   at Xamarin.Forms.Platform.WinPhone.VisualElementPackager.HandleChildAdded(Object sender, ElementEventArgs e)
   at Xamarin.Forms.Platform.WinPhone.VisualElementPackager.Load()
   at Xamarin.Forms.Platform.WinPhone.VisualElementRenderer`2.SetElement(VisualElement element)
   at Xamarin.Forms.Platform.WinPhone.RendererFactory.GetRenderer(VisualElement view)
   at Xamarin.Forms.Platform.WinPhone.ScrollViewRenderer.LoadContent()
   at Xamarin.Forms.Platform.WinPhone.ScrollViewRenderer.OnElementChanged(ElementChangedEventArgs`1 e)
   at Xamarin.Forms.Platform.WinPhone.VisualElementRenderer`2.SetElement(VisualElement element)
   at Xamarin.Forms.Platform.WinPhone.RendererFactory.GetRenderer(VisualElement view)
   at Xamarin.Forms.Platform.WinPhone.VisualElementPackager.HandleChildAdded(Object sender, ElementEventArgs e)
   at Xamarin.Forms.Platform.WinPhone.VisualElementPackager.Load()
   at Xamarin.Forms.Platform.WinPhone.VisualElementRenderer`2.SetElement(VisualElement element)
   at Xamarin.Forms.Platform.WinPhone.RendererFactory.GetRenderer(VisualElement view)
   at Xamarin.Forms.Platform.WinPhone.NavigationPageRenderer.<OnElementChanged>b__0()
   at Xamarin.Forms.Platform.WinPhone.NavigationPageRenderer.OnElementChanged(ElementChangedEventArgs`1 e)
   at Xamarin.Forms.Platform.WinPhone.VisualElementRenderer`2.SetElement(VisualElement element)
   at Xamarin.Forms.Platform.WinPhone.RendererFactory.GetRenderer(VisualElement view)
   at Xamarin.Forms.Platform.WinPhone.MasterDetailRenderer.LoadDetail()
   at Xamarin.Forms.Platform.WinPhone.MasterDetailRenderer.OnElementChanged(ElementChangedEventArgs`1 e)
   at Xamarin.Forms.Platform.WinPhone.VisualElementRenderer`2.SetElement(VisualElement element)
   at Xamarin.Forms.Platform.WinPhone.RendererFactory.GetRenderer(VisualElement view)
   at Xamarin.Forms.Platform.WinPhone.Platform.SetCurrent(Page page, Boolean animated, Boolean popping, Action completedCallback)
   at Xamarin.Forms.Platform.WinPhone.Platform.SetPage(Page newRoot)
   at Xamarin.Forms.Forms.ConvertPageToUIElementWithoutApp(Page page, PhoneApplicationPage applicationPage)
   at Xamarin.Forms.Platform.WinPhone.FormsApplicationPage.SetMainPage()
   at Xamarin.Forms.Platform.WinPhone.FormsApplicationPage.LoadApplication(Application application)
   at MatrixGuide.WinPhone.MainPage..ctor()
   --- End of inner exception stack trace ---
   at System.Windows.Navigation.PageResourceContentLoader.EndLoad(IAsyncResult asyncResult)
   at System.Windows.Navigation.NavigationService.ContentLoader_BeginLoad_Callback(IAsyncResult result)}    System.Exception {System.Reflection.TargetInvocationException}

Has anybody an idea what that can be…?

Thanks for any suggestion