Hi John,
Thank you for using Syncfusion products.
I am afraid, that I was unable to reproduce this issue. Can you please provide us more information regarding the issue with a simple sample. so that we could sort out the cause of the issue and provide you a solution.
Please refer the following documentation links to have an better idea about the chart series and legend items.
http://help.syncfusion.com/ug_82/WindowsFormsUI_Chart/ChartLegend.htmlhttp://help.syncfusion.com/ug_82/WindowsFormsUI_Chart/ChartSeries.htmlLet me know if it helps.
Regards,
Jaffer.B