Thank you for giving a try to GroupDocs.Comparison for .NET API.
From your inquiry we are not sure about version of GroupDocs.Comparison for .NET API you are using? Please share some details regarding API version.
I see that a new worksheet is created for every worksheet where changes are found.
What is the naming convention though?
if you are trying API without applying license then new sheet name should be like “Evaluation Warning” where you will find the text regarding Evaluation.
and if you are applying license then new sheet should be like “Summary Page” where you will find the text regrading changes detected.
In my example the original worksheet name was Sheet1. The newly created worksheet was named Sheet10a303360
We are unable to re-produce this at our end. kindly share your sample "source and target " files with us. kindly also share your sample code if you are using other than our hosted example on GitHub.
Thank you for your cooperation.