As we suggested earlier kindly do try using our latest version/fix: Aspose.Cells for .NET v17.11.x. I observed the issue as you mentioned by converting your template file “21st century pie chart1 - Original.xlsx” to PDF file format. I found the Pie chart looses 3D effects in the output PDF. But I also confirmed the values (data labels) formatting is Ok with v17.11.x.
I have logged your issue as following:
- CELLSNET-45787 - Pie chart looses 3D effects in the output PDF
Once we have an update on it, we will let you know here.