I'm able to setup and bind a chart very easily using the following code:

      Dim rand As New Random(DateTime.UtcNow.Millisecond)
      Dim col As New DataCollection
      col.Add(#2/1/2023#, rand.NextDouble)
      col.Add(#2/2/2023#, rand.NextDouble)
      col.Add(#2/8/2023#, rand.NextDouble)

      Dim sharedXAxis As New TimeXAxis With {.LabelLocation = AxisLabelsLocation.OutsideBottom, .DataSource = col, .DateTimeMemberPath = "X"}
      sharedXAxis.LabelFormats.Add(New TimeAxisLabelFormat With {.Format = "HH:mm"})
      Me.UltraDataChart1.Axes.Add(sharedXAxis)

      Dim yAxis1 As New NumericYAxis With {.LabelLocation = AxisLabelsLocation.OutsideLeft, .MinimumValue = 0, .MaximumValue = 1}
      Me.UltraDataChart1.Axes.Add(yAxis1)

      Dim series1 As New LineSeries With {.DataSource = col, .ValueMemberPath = "Y", .XAxis = sharedXAxis, .YAxis = yAxis1}

      Me.UltraDataChart1.Series.Add(series1)

The DataCollection class was adapted from the one defined here.

The above code works as expected.  But if I try to add another item to the DataCollection after the LineSeries is added to the UltraDataChart, I get an ArgumentOutOfRangeException with the following stack trace:

at System.ThrowHelper.ThrowArgumentOutOfRange_IndexException()
at System.Collections.Generic.List`1.InsertRange(Int32 index, IEnumerable`1 collection)
at Infragistics.Portable.FastItemsSource.DataSourceAdd(Int32 position, IList newItems)
at ChartTester.DataCollection.Add(DateTime x, Double y) in D:\Source\DOTNET\TestProjects\ChartTester\Form1.vb:line 94
at ChartTester.Form1.Form1_Load(Object sender, EventArgs e) in D:\Source\DOTNET\TestProjects\ChartTester\Form1.vb:line 55

I'm sure there's something really obvious that I'm missing.  Any suggestions would be greatly appreciated.

Edit: forgot to specify that I'm using Infragistics Windows Forms 22.1 and .NET 6.

Edit 2: here's the code for the DataCollection and DataPoint classes.

Public Class DataCollection
   Implements INotifyCollectionChanged
   Implements IEnumerable

   Protected Data As New List(Of DataPoint)

   Public Event CollectionChanged As NotifyCollectionChangedEventHandler Implements INotifyCollectionChanged.CollectionChanged

   Protected Sub OnCollectionChanged(e As NotifyCollectionChangedEventArgs)
      RaiseEvent CollectionChanged(Me, e)
   End Sub

   Public Function GetEnumerator() As IEnumerator Implements IEnumerable.GetEnumerator
      Return Me.Data.GetEnumerator
   End Function

   Public Sub Add(x As DateTime, y As Double)
      Dim dataPoint As New DataPoint(x, y)
      Me.Data.Add(dataPoint)
      Me.OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, dataPoint))
   End Sub

End Class

Public Class DataPoint

   Public ReadOnly Property X As DateTime

   Public ReadOnly Property Y As Double

   Public Sub New(x As DateTime, y As Double)
      Me.X = x
      Me.Y = y
   End Sub

End Class