Hi Chanida,
Thank you for contacting Aspose support.
We have evaluated your presented scenario while using the latest version of Aspose.Cells for .NET 8.2.1.3, and we are able to replicate the problem of “unreadable contents” when resultant file is loaded with MS Excel. Please note, we have tested the case by loading your provided spreadsheet in an instance of Workbook, and re-saved it without any further processing.
Please spare us little time to properly analyze the problem on our end that we have logged as CELLSNET-43064 for further investigation. Once we have isolated the problem cause, we will be in a better position to estimate the schedule for the fix. In the meanwhile, we will keep you posted with updates in this regard.