To reproduce:

public Form1()
{
    InitializeComponent();
    this.radListView1.AllowDragDrop = true;
    for (int i = 0; i < 3; i++)
    {
        this.radListView1.Items.Add("Item" + i);
    }

    this.radListView1.ListViewElement.DragDropService.Started += DragDropService_Started;
    this.radListView1.ListViewElement.DragDropService.Stopped += DragDropService_Stopped;
}

private void DragDropService_Stopped(object sender, EventArgs e)
{
    Console.WriteLine("Stopped " + this.radListView1.SelectedIndex);
}

private void DragDropService_Started(object sender, EventArgs e)
{
    Console.WriteLine("Started " + this.radListView1.SelectedIndex);
}

Drag an item and drop it on a new position. As a result the SelectedIndexChanged event is fired and the new index is -1. There is no selected item in the RadListView.

Workaround: use a custom RadListView.ListViewElement.DragDropService and set the SelectedItem property to be equal to the CurrentItem when the drop operation is completed.

public class CustomService : ListViewDragDropService
{
    public CustomService(RadListViewElement owner) : base(owner)
    {
    }

    protected override void OnPreviewDragDrop(Telerik.WinControls.RadDropEventArgs e)
    {
        base.OnPreviewDragDrop(e);
        this.Owner.SelectedItem = this.Owner.CurrentItem;
    }
}