Something that I had to debug today was a case where the raw data for a chart contained duplicate series names. When I created the chart in PowerPoint using Aspose.Slides it did work but the chart data workbook does not open.
I have observed the issue statement shared by you and request you to please provide the source presentation, sample code and generated presentation reproducing the issue. I will be able to investigate the issue further on my end on provision of requested information.
Code is straightforward. Taking the 3 default series and giving them the same name.
The issues you have found earlier (filed as SLIDESJAVA-34980) have been fixed in this update.