Evaluation Aspose.Cells unable to save twice?

I am currently evaluating Aspose.Cells. I am trying to save a workbook twice. On the second save I get an empty workbook (just the evaluation warning). Is this a feature of the Evaluation copy?

AE

When calling Workbook.Save method, data in Workbook object is reset. To save a workbook twice, you can use Excel.Copy method to create a copy.

I will check if we can allow to save a workbook multiple times in future versions.