Commented Issue: Unreadable contents found after using xlPackage.Save() [14813]

Here's the code I'm using, but keep on getting unreadable error when try to open the saved file with Excel 2010.
FileInfo regFile = new FileInfo(@"mysample.xlsx");
using (ExcelPackage xlPackage = new ExcelPackage(regFile))
{

ExcelWorksheet allApp = xlPackage.Workbook.Worksheets[1];

allApp.Cells[2, 1].Value = "1";

xlPackage.Save();

}

Everything works fine, and after I repair the excel file, the sheet has been changed to what I wanted, just the above error came out when I open the excel file.
I believe is the way Epplus writes xml is different from what Excel expects? Can anyone help?
Comments: I second this. Perhaps an important info to fix the issue: In EPPlus 3.0.0.2 all works fine.