Crash when animating Hub.Orientation?

I'm trying to animate Hub.Orientation and getting an unhandled exception / catastrophic failure when moving to the "Vertical" state. The full code is below. Did I make a typo or could this be a bug? It works fine if I set the Orientation in code-behind. Thanks!

<Page
    x:Class="App4.MainPage"
    xmlns="http://ift.tt/w9rHWX;
    xmlns:x="http://ift.tt/1idQEwn;

        <StackPanel>
                
                <VisualStateManager.VisualStateGroups>
                        <VisualStateGroup x:Name="OrientationStates">
                                <VisualState x:Name="Horizontal" />
                                <VisualState x:Name="Vertical">
                                        <Storyboard>
                                                <ObjectAnimationUsingKeyFrames Storyboard.TargetName="hub" Storyboard.TargetProperty="Orientation">
                                                        <DiscreteObjectKeyFrame KeyTime="0:0:0" Value="Vertical" />
                                                </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                </VisualState>
                        </VisualStateGroup>
                </VisualStateManager.VisualStateGroups>
                
                <Button Content="Vertical"   Click="OnVerticalClick" />
                <Button Content="Horizontal" Click="OnHorizontalClick" />

                <Hub x:Name="hub" />

        </StackPanel>
</Page>

using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

namespace App4
{
    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();
        }

        void OnVerticalClick  (object sender, RoutedEventArgs e) { VisualStateManager.GoToState(this, "Vertical",   false); }
        void OnHorizontalClick(object sender, RoutedEventArgs e) { VisualStateManager.GoToState(this, "Horizontal", false); }
    }
}