After an initial test, I observed the issue you mentioned by using your sample code with your template file, The charts are not rendered fine when re-saving the file. I have logged a ticket with an id “CELLSJAVA-41128” for your issue. We will look into it soon.
Once we have any update on it, we will let you know here.
Check the length of your footers and headers, I've had the same issue when they're over the char limit.
Hi,
Thanks for your posting and considering Aspose.Cells.
Kindly post your issue in a New Post with your sample Excel file and sample code, so that we could investigate your issue and log it in our database for a fix.