Using more colors than rows in a pie chart using the Chart Macro throws an error

2014-10-02 10:04:14,940 ERROR [http-8090-10] [xhtml.view.macro.ViewMacroMarshaller] marshal Error rendering macro: chart
 -- referer: https://lge1as061t/confluence/display/ASQ/Self+service+reports | url: /confluence/display/ASQ/Self+service+reports | userName: gpuccianiADM | action: viewpage | page: 4096062
java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer
        at java.lang.Integer.compareTo(Unknown Source)
        at java.util.TreeMap.put(Unknown Source)
        at org.jfree.chart.PaintMap.put(PaintMap.java:125)
        at org.jfree.chart.plot.PiePlot.setSectionPaint(PiePlot.java:849)
        at org.jfree.chart.plot.PiePlot.setSectionPaint(PiePlot.java:878)
        at com.atlassian.confluence.extra.chart.ChartMacro.handleColorCustomization(ChartMacro.java:887)
        at com.atlassian.confluence.extra.chart.ChartMacro.getChart(ChartMacro.java:686)
        at com.atlassian.confluence.extra.chart.ChartMacro.getChartImage(ChartMacro.java:418)
        at com.atlassian.confluence.extra.chart.ChartMacro.execute(ChartMacro.java:321)