Custom Indicator draws a ChartHorizontalLine. How do access this object in a Robot?

I have an Indicator that draws a ChartHorizontalLine. Here's a simplified example:

using cAlgo.API;

namespace cAlgo.Indicators
{
    [Indicator(IsOverlay = true, AccessRights = AccessRights.None)]
    public class MyIndicator : Indicator
    {
        public ChartHorizontalLine? MyHorizontalLine { get; set; }
    
    	// ...
    
    	public override void Calculate(int index)
    	{
    		MyHorizontalLine = Chart.DrawHorizontalLine("MyHorizontalLine", Ask - Symbol.PipSize * 10, Color.Green);
    	}
    
    	// ...
}

I also have a Robot that tries to look for the chart objects, e.g.:

using cAlgo.API;

namespace cAlgo.Robots
{
    [Robot(AccessRights = AccessRights.None)]
    public class MyRobot : Robot
    {
        // ...

        protected override void OnTick()
        {
            Print("Chart.Objects.Count: ", Chart.Objects.Count);
            
            if (Chart.FindObject("MyHorizontalLine") is ChartHorizontalLine MyHorizontalLine)
            {
                Print("MyHorizontalLine.Y: ", MyHorizontalLine.Y);
            }
        }

        // ...
    }
}

The line appears on the chart when the Indicator is running but the Robot cannot see the object and prints 0.

Running the print statement in the indicator returns the expected 1.

Is it possible to make the horizontal line from the indicator available as a chart object by name to the Robot? 

I don't see the horizontal line as an object in the objects manager, either in the Drawing or Indicators panels.