To reproduce:
- Start the Q3 2014 SP1 demo application.
- Open the Bar example.
- Set the orientation to horizontal.

In addition please note that the first and the last labels of the horizontal axis are missing as well.

Workaround:

CategoricalAxis vertiacalAxis = radChartView1.Axes[1] as CategoricalAxis;

if (vertiacalAxis != null)
{
    vertiacalAxis.LabelFitMode = AxisLabelFitMode.Rotate;
    vertiacalAxis.LabelRotationAngle = .1;
}