How to push onto Navigation Page's stack within a Tabbed Page - xamarin.forms

Question

I am using MvvmCross and Xamarin Forms. My app's main page is a MvxTabbedPage with four tabs. Each of the tabs are Navigation Pages that contain their own Content Pages. No matter which tab is current, any Navigate call to IMvxNavigationService pushes the page onto the first tab.
A printout of Application.Current.Hierarchy() looks like this:
Application Root
HomePage(Tabbed)
[0]: MvxNavigationPage(Navigation)
[0]: FirstPage(Content)
[1]: MvxNavigationPage(Navigation)
[0]: SecondPage(Content)
[2]: MvxNavigationPage(Navigation)
[0]: ThirdPage(Content)
[3]: MvxNavigationPage(Navigation)
[0]: FourthPage(Content)
Initiating a Navigate to DetailsPage from the second tab results in this hierarchy:
Application Root
HomePage(Tabbed)
[0]: MvxNavigationPage(Navigation)
[0]: FirstPage(Content)
[1]: DetailsPage(Content)
[1]: MvxNavigationPage(Navigation)
[0]: SecondPage(Content)
[2]: MvxNavigationPage(Navigation)
[0]: ThirdPage(Content)
[3]: MvxNavigationPage(Navigation)
[0]: FourthPage(Content)
In an attempt to debug, I attached a handler to the CurrentPageChanged event on my MvxTabbedPage and I can confirm that the CurrentPage is updated correctly. I've also tried settings WrapInNavigationPage = true for the TabbedPage, but it resulted in undesirable navigation behavior.
HomePage.xaml (no Code-behind):
<?xml version="1.0" encoding="UTF-8"?>
<views:MvxTabbedPage
xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:views="clr-namespace:MvvmCross.Forms.Views;assembly=MvvmCross.Forms"
xmlns:mvx="clr-namespace:MvvmCross.Forms.Bindings;assembly=MvvmCross.Forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:local="clr-namespace:Ketchup.Core.Views"
xmlns:viewModels="clr-namespace:Ketchup.Core.ViewModels;assembly=Ketchup.Core"
x:Class="Ketchup.Core.Views.HomePage"
x:TypeArguments="viewModels:HomeViewModel"
ItemTemplate="{mvx:MvxBind DataTemplateSelector}"
ItemsSource="{mvx:MvxBind TabViewModels}"
xmlns:android="clr-namespace:Xamarin.Forms.PlatformConfiguration.AndroidSpecific;assembly=Xamarin.Forms.Core"
android:TabbedPage.ToolbarPlacement="Bottom"
>
</views:MvxTabbedPage>
HomePageViewModel.cs
public class HomeViewModel : MvxViewModel
{
// Bound Property
List<IMvxViewModel> _tabViewModels;
public List<IMvxViewModel> TabViewModels
{
get
{
return _tabViewModels;
}
set
{
_tabViewModels = value;
RaisePropertyChanged(() => TabViewModels);
}
}
// Bound Property
public TabDataTemplateSelector DataTemplateSelector
{
get;
set;
}
// ...
public class TabDataTemplateSelector : DataTemplateSelector
{
private IMvxViewsContainer _viewsContainer;
protected IMvxViewsContainer ViewsContainer
{
get
{
if (_viewsContainer == null)
_viewsContainer = Mvx.IoCProvider.Resolve<IMvxViewsContainer>();
return _viewsContainer;
}
}
Dictionary<IMvxViewModel, DataTemplate> Cache;
public TabDataTemplateSelector()
{
Cache = new Dictionary<IMvxViewModel, DataTemplate>();
}
protected override DataTemplate OnSelectTemplate(object item, BindableObject container)
{
Console.WriteLine("Get Data Template for Object {0}", item);
DataTemplate _dataTemplate = null;
IMvxViewModel viewModel = item as IMvxViewModel;
Type viewType;
if (item != null)
{
if (Cache.ContainsKey(viewModel))
{
Console.WriteLine("Tab in cache, returning cached data.");
_dataTemplate = Cache[viewModel];
}
else
{
viewType = ViewsContainer.GetViewType(viewModel.GetType());
Console.WriteLine("View Type {0}, ViewModel {1}", viewType, viewModel);
_dataTemplate = new DataTemplate(() =>
{
IMvxView view = (IMvxView)Activator.CreateInstance(viewType);
view.DataContext = viewModel;
Page page = (Page)view;
MvxNavigationPage navigationPage = new MvxNavigationPage(page);
navigationPage.Title = page.Title;
navigationPage.Icon = page.Icon;
return navigationPage;
});
// Cache DataTemplate
Cache[viewModel] = _dataTemplate;
}
}
return _dataTemplate;
}
}
// ... End of HomeViewModel class
Any help or pointers are greatly appreciated!
Other notes:
The tabbed page has these attributes: [MvxTabbedPagePresentation(TabbedPosition.Root, NoHistory = true, WrapInNavigationPage = false)]
The ItemSource property is a List of MvxViewModel objects.
The ItemTemplate property is a DataTemplate that instantiates the corresponding Page and wraps it in a NavigationPage.
MvvmCross 6.2.2, Xamarin Forms 3.4