Please try the latest version:
for .NET v126.96.36.199
and let us know your feedback.
If the problem persists, then provide us your sample source and output xls/xlsx file which you can create manually using Ms-Excel and the complete sample code you are using.
I don’t use the latest version because I generate more report in my project and I convert more file.
Please refer to this post and see if it is useful for you.
I apply one workaround, set the property X and Y of the DataLabels.
It’s good to know your problem is finally resolved.
Please feel free to ask any other question, we will help you asap.