Hi Adrian,
This has been identified as a bug and I have filed a bug report with
the development team. You can track the live status of this issue here
http://www.syncfusion.com/support/issues/xlsio/Default.aspx?ToDo=view&questId=1149
If you are not modifying any chart properties using XlsIO then please
use the option to not parse excel charts while opening the template
IWorkbook workbook = excelEngine.Excel.Workbooks.Open
("Template.xls",ExcelParseOptions.DoNotParseCharts);
Herewith i attach a sample. Please take a look and let me know if you have any questions.
f38052ChartLegend.zip
Thanks,
Ramu.K