When specifiying a chart type of columnStacked, I get the following chart. If I edit the Excel file generated, change the chart type to something else then back to columnStacked, the chart appears as expected. We need to put this chart into Production very soon. Sample code is attached.
ChartTestColumnStackedChart.zip
Thanks for bringing this to our attention. The problem here is that WorksheetChart.SeriesOverlap is not defaulting to 100%, as it does when you create a chart through MS Excel's UI; this will be fixed is an upcoming SR.
In the meantime you can work around this by setting WorksheetChart.SeriesOverlap to 100.
The work around has fixed the problem. Thank you.