StrokeDashArray Binding Not Working for FastLineRenderableSeries / GridLineStyle

I am trying to bind StrokeDashArray to a property in my ViewModel, which is an enum (Solid, Dash, Dot), using a value converter.

The binding works as expected for HorizontalLineAnnotation, but it does not work for FastLineRenderableSeries or MajorGridLineStyle.

Works

<s:HorizontalLineAnnotation StrokeDashArray="{Binding LineStyle, Converter={StaticResource DashConverter}}" />
<s:FastLineRenderableSeries StrokeDashArray="4,4" />

Does NOT work, always display solid line

<s:FastLineRenderableSeries StrokeDashArray="{Binding LineStyle, Converter={StaticResource DashConverter}}" />

Converter Code

public enum LineStyle { Solid, Dash, Dot }

public class DashConverter : IValueConverter
{
   public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
   {
      Enum.TryParse(value.ToString(), out LineStyle lineStyle);
      switch (lineStyle)
      {
         case LineStyle.Dash:
            return new DoubleCollection(new double[] { 4, 4 });
         case LineStyle.Dot:
            return new DoubleCollection(new double[] { 1, 4 });
      }
   return new DoubleCollection();//Solid
}