Using the following code:

    private void InitializeChart()
    {
      tChart1.Aspect.View3D = false;

      Line line1 = new Line(tChart1.Chart);
      line1.FillSampleValues(100);

      ScrollPager scroll = new ScrollPager(tChart1.Chart);
      scroll.Series = line1;
    }

    private void button2_Click(object sender, EventArgs e)
    {
      MemoryStream stream = new MemoryStream();

      tChart1.Export.Template.Save(stream);
      stream.Position = 0;
      tChart2.Import.Template.Load(stream);

      ScrollPager tool = tChart2.Tools[0] as ScrollPager;
      MessageBox.Show((tool.Series == null).ToString());

      tool.Series = tChart2[0];
    }

we can see that although the Series property is not null, it has to be reassigned for the Chart to render accurately.