Meanwhile, you can workaround this by resetting the property every time you change the number of months that RadCalendar displays. This is shown in the next code snippet:

private void radPageViewPage2_ClientSizeChanged(object sender, EventArgs e)
{
    int numViews = this.radPageViewPage2.Size.Height / 240 + 1;
    radCalendar1.MultiViewRows = numViews;
    radCalendar1.ShowFastNavigationButtons = true;
    radCalendar1.ShowFastNavigationButtons = false;
}