How to reproduce: 
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        this.radChartView1.AreaType = ChartAreaType.Pie;
        PieSeries series = new PieSeries();
        series.DataPoints.Add(new PieDataPoint(0, "Germany"));
        series.DataPoints.Add(new PieDataPoint(0, "United States"));
        series.DataPoints.Add(new PieDataPoint(0, "France"));
        series.DataPoints.Add(new PieDataPoint(0, "United Kingdom"));
        series.ShowLabels = true;
        this.radChartView1.Series.Add(series);
        this.radChartView1.ShowSmartLabels = true;
    }
}

Workaround: 
this.radChartView1.ShowSmartLabels = false;