Android - MasterDetailsView - DetailsTemplate not working

[TopperDEL]

Describe the bug

I have a MasterdetailsView bound to an ObservableCollection and set the ItemTemplate and DetailsTemplate with a DataTemplate set with x:DataType="ViewModel". The ItemTemplate works, but the DetailsTemplate is not rendered correctly. It only shows the string with the full qualified name of my ViewModel-class.

Steps to Reproduce

1. Add a MasterDetailsView
2. Bind it to a collection
3. Add ItemTemplate and DetailsTemplate with x:DataType bound to your ViewModel
4. Run the app - the DetailsTemplate is not rendered

Expected behavior

The DetailsTemplate gets rendered as it is on UWP.

Environment

NuGet Package(s): Uno.Microsoft.Toolkit.Uwp.UI-Controls v6.1.0-build.191.gc988bdd4ff

Package Version(s): 

Device form factor:
- [ ] Windows
- [ ] macOS
- [?] iOS
- [X] Android
- [ ] WebAssembly
- [ ] WebAssembly renderers for Xamarin.Forms

Visual Studio 
- [ ] 2017 (version: )
- [ ] 2019 (version: ) 
- [X] 2019 Preview (version: 16.7.0 Preview 5.0)

[TopperDEL]

I found out that the error comes from a TextBox within the DataTemplate of the DetailsTemplate that has a HeaderTemplate set like this:

<TextBox Text="Test" >
     <TextBox.HeaderTemplate>
          <DataTemplate></DataTemplate>
     </TextBox.HeaderTemplate>
</TextBox>

A repro can be found here. Just uncomment lines 24 to 26 and Android will only render the Name of the Model within the DetailsTemplate.

@jeromelaban