Thanks for your posting and using Aspose.Cells.
If you manually save your Excel file into HTML format, you will see Microsoft Excel also displays cell D4 as 1 instead of 100%.
So, this is not the bug of Aspose.Cells but a correct behavior.
I use MS Excel 2007.
regarding Numbers format when rendering to HTML file format. I have logged a ticket with an id “CELLSJAVA-41150” for your issue. We will look into it soon.
Thanks for using Aspose.Cells.
We have fixed this issue.
Please download and try the latest fix: Aspose.Cells
for Java v126.96.36.199 and let us know your feedback.