Is this a Datagrid WPF bug?

I have the following proof of concept:

XAML window:

<Window x:Class="WpfApplication1.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">

<DataGrid ItemsSource="{Binding Items}" AutoGenerateColumns="False" >
    <DataGrid.Columns>
        <DataGridTextColumn Binding="{Binding Name}" />
        <DataGridTemplateColumn >
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <CheckBox IsChecked="{Binding Mode=TwoWay, Path=Enabled}" />
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
    </DataGrid.Columns>
</DataGrid>
</Window>

Code behind:

using System.Collections.ObjectModel;
using System.Windows;

namespace WpfApplication1
{
public partial class MainWindow : Window
{
    public ObservableCollection<Data> Items { get; private set; }

    public MainWindow()
    {
        InitializeComponent();
        this.Items = new ObservableCollection<Data>();
        this.DataContext = this;
        for (int index = 0; index < 30; index++)
        {
            this.Items.Add(new Data() {Enabled = true });   
        }
    }
}

public class Data
{
    public bool Enabled { get; set; }
}
}

Launch the application, uncheck the boxes next to them, scroll down, change some fields again and scroll up. Voilá, the flags are checked again!

Am I missing something or should I fill out a Microsoft error?

EDIT . Thanks for your answers, but this is not related to INotify or Checkbox, with TextBox and INotify this happens. You do not need to specify the flags after scrolling, just uncheck the box, scroll down, scroll up and voila, they will be checked again. Check this code:

<DataGrid ItemsSource="{Binding Items}" AutoGenerateColumns="False" >
    <DataGrid.Columns>
        <DataGridTemplateColumn >
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal">
                        <CheckBox IsChecked="{Binding Mode=TwoWay, Path=Enabled}" />
                        <TextBox Text="{Binding Text}" />
                    </StackPanel>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
    </DataGrid.Columns>
</DataGrid>
</Window>

And the code behind:

using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Windows;

namespace WpfApplication1
{
public partial class MainWindow : Window
{
    public ObservableCollection<Data> Items { get; private set; }

    public MainWindow()
    {
        InitializeComponent();
        this.Items = new ObservableCollection<Data>();
        this.DataContext = this;
        for (int index = 0; index < 30; index++)
        {
            this.Items.Add(new Data() { Enabled = true, Text = index.ToString() });
        }
    }
}

public class Data : INotifyPropertyChanged
{
    private bool _enabled;
    public bool Enabled
    {
        get { return _enabled; }
        set
        {
            if (value != _enabled)
            {
                _enabled = value;
                this.OnPropertyChanged("Enabled");
            }
        }
    }

    private string _text;
    public string Text
    {
        get { return _text; }
        set
        {
            if (value != _text)
            {
                _text = value;
                this.OnPropertyChanged("Text");
            }
        }
    }

    #region INotifyPropertyChanged Members

    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged(string name)
    {
        if (this.PropertyChanged != null)
        {
            this.PropertyChanged(this, new PropertyChangedEventArgs(name));
        }
    }

    #endregion
}
}