ComboBox SelectedIndex secretly changes in x:Bind

[HO-COOH]

Describe the bug

I have this runtime type

    [bindable]
    [default_interface]
    runtimeclass MyData
    {
        MyData();
        Int32 Index{ get; set; };
        Windows.Foundation.Collections.IObservableVector<String> Versions{ get; };
    }

And the code behind

    struct MyData : MyDataT<MyData>
    {
        MyData() = default;

        int Index() 
        { 
            return m_index; 
        }

        void Index(int index) 
        { 
            m_index = index; 
        }

        winrt::Windows::Foundation::Collections::IObservableVector<winrt::hstring> Versions() { return m_versions; }
        winrt::Windows::Foundation::Collections::IObservableVector<winrt::hstring> m_versions = winrt::single_threaded_observable_vector<winrt::hstring>();
        int m_index = 0;
    };

I have a ListView in MainPage.xaml using ItemTemplate

        <ListView ItemsSource="{x:Bind data}">
            <ListView.ItemTemplate>
                <DataTemplate x:Name="template" x:DataType="local:MyData">
                    <ComboBox x:Name="box" SelectedIndex="{x:Bind Index}" ItemsSource="{x:Bind Versions}"/>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>

MainPage.idl

    [default_interface]
    runtimeclass MainPage : Windows.UI.Xaml.Controls.Page
    {
        MainPage();
        Windows.Foundation.Collections.IObservableVector<MyData> data{ get; };
    }

Fill the data in the code-behind

    MainPage::MainPage()
    {
        InitializeComponent();
        for (int i = 0; i < 1000; ++i)
        {
            MyData newData;
            newData.Versions().Append(L"A");
            newData.Versions().Append(L"B");
            newData.Versions().Append(L"C");
            newData.Versions().Append(L"D");
            m_data.Append(newData);
        }
    }

Steps to reproduce the bug

1. Launch the app, and scroll a little bit down. You can see most of those ComboBox are not populated. Put a break point in the Index setter in the MyData.cpp, you can see the parameters are given a value of -1, while the m_index is actually initialized to 0

Expected behavior

No response

Screenshots

NuGet package version

Microsoft.UI.Xaml 2.8.0

Windows app type

• UWP
• Win32

Device form factor

Desktop

Windows version

Windows 11 (22H2): Build 22621

Additional context

No response

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