在 UWP 中设置链接时 RichEditBox 的这种模棱两可的行为是什么

Question

public MainPage()
        {
            this.InitializeComponent();
            box1 = new RichEditBox()
            {
                Width = 500,
                Height = 500,
                BorderBrush = new SolidColorBrush(Colors.Blue),
                BorderThickness = new Thickness(1, 1, 1, 1)
            };
            btn = new Button() { Content = "button" };
            btn.Click += Btn_Click;
            string str = "ppppppavaniiiiipavanlllllpavankjhgfcdsa";
            box1.Document.SetText(0, str);
            box1.TextAlignment = TextAlignment.Center;

            {
                ITextSelection selection1 = box1.Document.Selection;

                selection1.StartPosition = 5;
                selection1.EndPosition = 10;
                Debug.WriteLine("<<<<<<<<<<<<<<<<<<<<<" + selection1.StartPosition);
                Debug.WriteLine("<<<<<<<<<<<<<<<<<<<<<" + selection1.EndPosition);

                selection1.CharacterFormat.Bold = FormatEffect.On;

                string s = "\"google.com\"";
                selection1.Link = s;

                selection1.Collapse(false);
            }
            {
                ITextSelection selection2 = box1.Document.Selection;

                selection2.StartPosition = 25;
                selection2.EndPosition = 30;
                Debug.WriteLine("<<<<<<<<<<<<<<<<<<<<<" + selection2.StartPosition);
                Debug.WriteLine("<<<<<<<<<<<<<<<<<<<<<" + selection2.EndPosition);

                selection2.CharacterFormat.Bold = FormatEffect.On;
                selection2.CharacterFormat.Size = 20;
                selection2.CharacterFormat.BackgroundColor = Color.FromArgb(0, 50, 77, 98);
                selection2.CharacterFormat.Name = "Algerian";

                string s = "\"gjhgfdghje.com\"";
                selection2.Link = s;
            }

            grid.Children.Add(box1);
            grid.Children.Add(btn);
        }

在为 5 到 10 的范围设置

Link

之后，在为 25 到 30 的范围设置 Link 和 RichText 之前，一些如何应用到 5 到 10 的范围而不是 25 到 30 的范围。 这是输出

如果我将第二个代码块移动到第一个代码块之上，如下所示

        public MainPage()
        {
            this.InitializeComponent();
            box1 = new RichEditBox()
            {
                Width = 500,
                Height = 500,
                BorderBrush = new SolidColorBrush(Colors.Blue),
                BorderThickness = new Thickness(1, 1, 1, 1)
            };
            btn = new Button() { Content = "button" };
            btn.Click += Btn_Click;
            string str = "ppppppavaniiiiipavanlllllpavankjhgfcdsa";
            box1.Document.SetText(0, str);
            box1.TextAlignment = TextAlignment.Center;

            {
                ITextSelection selection2 = box1.Document.Selection;

                selection2.StartPosition = 25;
                selection2.EndPosition = 30;
                Debug.WriteLine("<<<<<<<<<<<<<<<<<<<<<" + selection2.StartPosition);
                Debug.WriteLine("<<<<<<<<<<<<<<<<<<<<<" + selection2.EndPosition);

                selection2.CharacterFormat.Bold = FormatEffect.On;
                selection2.CharacterFormat.Size = 20;
                selection2.CharacterFormat.BackgroundColor = Color.FromArgb(0, 50, 77, 98);
                selection2.CharacterFormat.Name = "Algerian";

                string s = "\"gjhgfdghje.com\"";
                selection2.Link = s;
            }
            {
                ITextSelection selection1 = box1.Document.Selection;

                selection1.StartPosition = 5;
                selection1.EndPosition = 10;
                Debug.WriteLine("<<<<<<<<<<<<<<<<<<<<<" + selection1.StartPosition);
                Debug.WriteLine("<<<<<<<<<<<<<<<<<<<<<" + selection1.EndPosition);

                selection1.CharacterFormat.Bold = FormatEffect.On;

                string s = "\"google.com\"";
                selection1.Link = s;

                selection1.Collapse(false);
            }
            grid.Children.Add(box1);
            grid.Children.Add(btn);
        }

那么输出就是这个

为什么这个行为是这样的