Behaviors in ControlTemplates

I have a ControlTemplate defined in App.xaml for pages with ListViews like so:

<ControlTemplate x:Key="BaseModelListPageTemplate">
    <StackLayout>
        <Label
        Text="{TemplateBinding BindingContext.Category}"
        BackgroundColor="Green"
        TextColor="White"
        FontSize="24"
        FontAttributes="Bold"/>
        <ListView
            x:Name="ItemListView"
            HasUnevenRows="true"
            ItemsSource="{TemplateBinding BindingContext.ItemsList}"
            IsPullToRefreshEnabled="true"
            IsRefreshing="{TemplateBinding BindingContext.IsBusy, Mode=OneWay}"
            RefreshCommand="{TemplateBinding BindingContext.ReloadCommand}"
            ItemTemplate="{StaticResource BaseModelDataTemplateSelector}">
            <ListView.Behaviors>
                <Behaviors:ListViewScrollBehavior Command="{TemplateBinding BindingContext.LoadMoreCommand}"/>
            </ListView.Behaviors>
        </ListView>
    </StackLayout>
</ControlTemplate>

All bindings compile with no errors. The trouble is that an InvalidOperationException gets thrown: Operation is not valid due to the current state of the object. It worked fine when it was directly in a page and not in a ControlTemplate.

StackTrace is of little help:

at Xamarin.Forms.TemplateBinding+<Apply>d__17.MoveNext () [0x00018] in C:\BuildAgent2\work\ca3766cfc22354a1\Xamarin.Forms.Core\TemplateBinding.cs:82 
--- End of stack trace from previous location where exception was thrown ---
  at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in /Users/builder/data/lanes/3969/7beaef43/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/referencesource/mscorlib/system/runtime/exceptionservices/exceptionservicescommon.cs:143 
  at System.Runtime.CompilerServices.AsyncMethodBuilderCore.<ThrowAsync>m__0 (System.Object state) [0x00000] in /Users/builder/data/lanes/3969/7beaef43/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/AsyncMethodBuilder.cs:1018 
  at UIKit.UIKitSynchronizationContext+<Post>c__AnonStorey0.<>m__0 () [0x00000] in /Users/builder/data/lanes/3969/7beaef43/source/xamarin-macios/src/UIKit/UIKitSynchronizationContext.cs:24 
  at Foundation.NSAsyncActionDispatcher.Apply () [0x00000] in /Users/builder/data/lanes/3969/7beaef43/source/xamarin-macios/src/Foundation/NSAction.cs:163 
  at (wrapper managed-to-native) UIKit.UIApplication:UIApplicationMain (int,string[],intptr,intptr)
  at UIKit.UIApplication.Main (System.String[] args, System.IntPtr principal, System.IntPtr delegate) [0x00005] in /Users/builder/data/lanes/3969/7beaef43/source/xamarin-macios/src/UIKit/UIApplication.cs:79 
  at UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x00038] in /Users/builder/data/lanes/3969/7beaef43/source/xamarin-macios/src/UIKit/UIApplication.cs:63 
  at EZDelivery.iOS.Application.Main (System.String[] args) [0x00008] in /Users/taylorartunian/Projects/EZDelivery/iOS/Main.cs:17