Two Y-axis graph: same line showing twice

I'm building a dashboard using the techniques described here on Splunkbase, so that I have two Y axes. What I'm seeing, however, is that there are two lines drawn for one of the data series. The legend only shows three sources. The second copy of the line hugs the X-axis line (as though it had Y value of zero). Attached is a screenshot. I can provide a sample of the XML, as well.

<param name="charting.data1.table">@data</param>
                          <param name="charting.data2.table">@data</param>
                          <param name="charting.data1.columms">[0,1,2]</param>
                          <param name="charting.data2.columms">[0,3]</param>
                          <param name="charting.chart.data">@data1</param>
                          <param name="charting.chart2.data">@data2</param>
                          <param name="charting.data1">view</param>
                          <param name="charting.data2">view</param>