[Skia] ContentPresenter: outgoing DataTemplate tree stays alive and rebinds when Content changes, letting its TwoWay bindings corrupt the new content's view model

<Page.Resources>
  <local:PickerTemplateSelector x:Key="PickerTemplateSelector">
    <local:PickerTemplateSelector.RadioTemplate>
      <DataTemplate x:DataType="local:PickerModel">
        <ItemsControl ItemsSource="{x:Bind Options}">
          <ItemsControl.ItemTemplate>
            <DataTemplate x:DataType="local:Option">
              <RadioButton Content="{x:Bind Label}" IsChecked="{x:Bind IsSelected, Mode=TwoWay}" GroupName="SharedGroup" />
            </DataTemplate>
          </ItemsControl.ItemTemplate>
        </ItemsControl>
      </DataTemplate>
    </local:PickerTemplateSelector.RadioTemplate>
    <local:PickerTemplateSelector.CheckBoxTemplate>
      <DataTemplate x:DataType="local:PickerModel">
        <ItemsControl ItemsSource="{x:Bind Options}">
          <ItemsControl.ItemTemplate>
            <DataTemplate x:DataType="local:Option">
              <CheckBox Content="{x:Bind Label}" IsChecked="{x:Bind IsSelected, Mode=TwoWay}" />
            </DataTemplate>
          </ItemsControl.ItemTemplate>
        </ItemsControl>
      </DataTemplate>
    </local:PickerTemplateSelector.CheckBoxTemplate>
  </local:PickerTemplateSelector>
</Page.Resources>

<StackPanel Padding="20" Spacing="12">
  <StackPanel Orientation="Horizontal" Spacing="8">
    <Button Content="Show radio field" Click="OnShowRadio" />
    <Button Content="Show checkbox field" Click="OnShowCheckBox" />
  </StackPanel>
  <ContentPresenter x:Name="Presenter" ContentTemplateSelector="{StaticResource PickerTemplateSelector}" />
  <TextBlock x:Name="StateText" FontFamily="Consolas" />
</StackPanel>

public sealed partial class MainPage : Page
{
    private readonly PickerModel _radioField = new(isMultiSelect: false, "Radio", ["Small", "Medium", "Large"]);
    private readonly PickerModel _checkBoxField = new(isMultiSelect: true, "CheckBox", ["Option A", "Option B", "Option C", "Option D"]);

    public MainPage()
    {
        InitializeComponent();

        foreach (var option in _radioField.Options.Concat(_checkBoxField.Options))
            option.PropertyChanged += (_, _) => UpdateStateText();

        Presenter.Content = _radioField;
        UpdateStateText();
    }

    private void OnShowRadio(object sender, RoutedEventArgs e) => Presenter.Content = _radioField;

    private void OnShowCheckBox(object sender, RoutedEventArgs e) => Presenter.Content = _checkBoxField;

    private void UpdateStateText() => StateText.Text = $"{_radioField}\n{_checkBoxField}";
}

public class PickerModel(bool isMultiSelect, string name, string[] optionLabels)
{
    public bool IsMultiSelect { get; } = isMultiSelect;
    public string Name { get; } = name;
    public ObservableCollection<Option> Options { get; } = [.. optionLabels.Select(l => new Option(l))];

    public override string ToString() =>
        $"{Name}: [{string.Join(", ", Options.Where(o => o.IsSelected).Select(o => o.Label))}]";
}

public class Option(string label) : INotifyPropertyChanged
{
    private bool _isSelected;

    public event PropertyChangedEventHandler? PropertyChanged;

    public string Label { get; } = label;

    public bool IsSelected
    {
        get => _isSelected;
        set
        {
            if (_isSelected == value)
                return;

            _isSelected = value;
            PropertyChanged?.Invoke(this, new(nameof(IsSelected)));
        }
    }
}

public partial class PickerTemplateSelector : DataTemplateSelector
{
    public DataTemplate? RadioTemplate { get; set; }
    public DataTemplate? CheckBoxTemplate { get; set; }

    protected override DataTemplate? SelectTemplateCore(object? item) => SelectTemplateCore(item, null!);

    protected override DataTemplate? SelectTemplateCore(object? item, DependencyObject container) =>
        item is PickerModel model ? (model.IsMultiSelect ? CheckBoxTemplate : RadioTemplate) : null;
}

private void ApplyContent(object? newContent)
{
    Presenter.Content = null;
    Presenter.ContentTemplate = null;

    if (newContent is not null)
    {
        Presenter.ContentTemplate = _selector.SelectTemplate(newContent, Presenter);
        Presenter.Content = newContent;
    }
}

at ChoiceOption.set_IsSelected(Boolean value)                        // false written into previously checked option
at ...FieldInputControl...SinChoTemΞ0...RadBut...TrySetInstance_xBind_21(ChoiceOption ___tctx, Object __value)
at Microsoft.UI.Xaml.Data.BindingExpression.UpdateSource(Object value)
at Microsoft.UI.Xaml.Controls.Primitives.ToggleButton.set_IsChecked(Nullable`1 value)
at Microsoft.UI.Xaml.Controls.RadioButton.UpdateRadioButtonGroup()   // radio group semantics kick in
at Microsoft.UI.Xaml.Controls.RadioButton.OnChecked()
at Microsoft.UI.Xaml.Controls.Primitives.ToggleButton.OnIsCheckedChanged()
at Microsoft.UI.Xaml.Data.BindingExpression.SetTargetValueForXBindSelector()   // leaked radio checked via binding
at Uno.UI.DataBinding.BindingPath.BindingItem.PropertyChangedValueHandler.NewValue()
at ChoiceOption.set_IsSelected(Boolean value)                        // true written by the user's CheckBox click
at ...FieldInputControl...MulChoTemΞ0...CheBox...TrySetInstance_xBind_24(ChoiceOption ___tctx, Object __value)
at Microsoft.UI.Xaml.Data.BindingExpression.UpdateSource(Object value)