BarIndicator is not updated when using GaugeRanges and their Min and Max properties are changed at runtime. The indicator's layout is updated only when the gauge control is re-sized.

Possible workaround:

Update measure and arrange the  BarIndicator control manually. 

        var size = this.BarIndicatorRanges1.RenderSize;
        this.BarIndicatorRanges1.Measure(Size.Empty);
        this.BarIndicatorRanges1.Measure(size);
 
        this.BarIndicatorRanges1.Arrange(new Rect(size));
        this.BarIndicatorRanges1.UpdateLayout();

As a workaround you need to use a ProportionalBrush mode instead.

The Visibility property of GaugeRange is not applied when it is set or bound in xaml

As a workaround if you set the Visibility in code after the range is loaded, the property's value is applied correctly.

If the numeric indicator is visualized on a large area (its container has large size), its segments are overlapping.

The visual elements generated for the GaugeRange objects are not cleared when you clear the Ranges collection of the scale. This happens if you call the Clear() method of the Ranges collection.

To work this around you can clear the ranges using the Remove() method instead of clear.

while (scale.Ranges.Count > 0)
{
    scale.Ranges.Remove(scale.Ranges.LastOrDefault());
}