To reproduce:

public Form1()
{
    InitializeComponent();

    Appointment a1 = new Appointment(new DateTime(2015, 03, 04, 10, 30, 0), TimeSpan.FromMinutes(30), "A1");
    Appointment a2 = new Appointment(new DateTime(2015, 03, 04, 11, 00, 0), TimeSpan.FromMinutes(30), "A2");
    Appointment a3 = new Appointment(new DateTime(2015, 03, 04, 11, 30, 0), TimeSpan.FromMinutes(30), "A3");
    this.radScheduler1.Appointments.Add(a1);
    this.radScheduler1.Appointments.Add(a2);
    this.radScheduler1.Appointments.Add(a3);
    DateTime currentDate = new DateTime(2015, 03, 03, 09, 00, 10);

    this.radScheduler1.FocusedDate = currentDate;
    SchedulerTimelineView timelineView = radScheduler1.GetTimelineView();
    timelineView.ShowTimescale(Timescales.Minutes);
    timelineView.RangeStartDate = currentDate.AddMonths(-3);
    timelineView.RangeEndDate = currentDate.AddMonths(3);
    timelineView.GetScaling().DisplayedCellsCount = 10;
}

Workaround: Use the date part only:
 DateTime currentDate = new DateTime(2015, 03, 03, 09, 00, 10);
 currentDate = currentDate.Date;