To reproduce:
        Me.RadScheduler1.ActiveViewType = Telerik.WinControls.UI.SchedulerViewType.Timeline
        Dim timelineView As SchedulerTimelineView = Me.RadScheduler1.GetTimelineView()
        Dim currentScaling As SchedulerTimescale = timelineView.GetScaling()
        currentScaling.DisplayedCellsCount = 100

Try to scroll horizontally. Then, change the currentScaling.DisplayedCellsCount  property to 50 and try to scroll again. You will notice a considerable difference.

Workaround: reduce the number of the displayed visual cell elements by the DisplayedCellsCount.