To reproduce:

public Form1()
{
    InitializeComponent();

    this.radScheduler1.GetDayView().RangeFactor = Telerik.WinControls.UI.ScaleRange.HalfHour;

    this.radScheduler1.Appointments.Add(new Appointment(new DateTime(2014, 7, 21, 11, 0, 0, 0),
                                                        new DateTime(2014, 7, 21, 12, 0, 0, 0)));

    this.radScheduler1.Appointments.Add(new Appointment(new DateTime(2014, 7, 21, 15, 30, 45, 137 ),
                                                        new DateTime(2014, 7, 21, 15, 30, 58, 600 )));

    this.radScheduler1.Appointments.Add(new Appointment(new DateTime(2014, 7, 21, 10, 0, 0, 0 ),
                                                        new DateTime(2014, 7, 21, 11, 0, 0, 0 )));

    this.radScheduler1.Appointments.Add(new Appointment(new DateTime(2014, 7, 21, 15, 30, 19, 633 ),
                                                        new DateTime(2014, 7, 21, 15, 30, 31, 253 )));

    this.radScheduler1.Appointments.Add(new Appointment(new DateTime(2014, 7, 21, 15, 29, 20, 337 ),
                                                        new DateTime(2014, 7, 21, 15, 29, 52, 767 )));

    this.radScheduler1.Appointments.Add(new Appointment(new DateTime(2014, 7, 21, 13, 0, 0, 0 ),
                                                        new DateTime(2014, 7, 21, 14, 0, 0, 0 )));

    this.radScheduler1.Appointments.Add(new Appointment(new DateTime(2014, 7, 21, 15, 0, 0, 0 ),
                                                        new DateTime(2014, 7, 21, 16, 0, 0, 0 )));

    this.radScheduler1.Appointments.Add(new Appointment(new DateTime(2014, 7, 21, 15, 28, 15, 500 ),
                                                        new DateTime(2014, 7, 21, 15, 28, 37, 310 )));

    this.radScheduler1.Appointments.Add(new Appointment(new DateTime(2014, 7, 21, 14, 0, 0, 0 ),
                                                        new DateTime(2014, 7, 21, 15, 0, 0, 0 )));

    this.radScheduler1.Appointments.Add(new Appointment(new DateTime(2014, 7, 21, 15, 27, 19, 123 ),
                                                        new DateTime(2014, 7, 21, 15, 27, 57, 357 )));
}