It looks like immediately after opening the spreadsheet using new XLWorkbook(...), the data in the original hasn't been loaded into memory:
(new System.Linq.SystemCore_EnumerableDebugView<ClosedXML.Excel.IXLWorksheet>(((ClosedXML.Excel.XLWorksheets)(spreadsheet.Worksheets)))).Items[10].Cell(2,1).Value
The above code returns an empty string, even though the original worksheet has a user's name in that cell. And so when I save the XLWorkbook, naturally the empty value gets saved resulting in the data loss about which I'm complaining.
Interestingly, ...Cell(1,1).Value returns "UserName" which is correct--it's the value of the cell serving as the column header.
(new System.Linq.SystemCore_EnumerableDebugView<ClosedXML.Excel.IXLWorksheet>(((ClosedXML.Excel.XLWorksheets)(spreadsheet.Worksheets)))).Items[10].Cell(2,1).Value
The above code returns an empty string, even though the original worksheet has a user's name in that cell. And so when I save the XLWorkbook, naturally the empty value gets saved resulting in the data loss about which I'm complaining.
Interestingly, ...Cell(1,1).Value returns "UserName" which is correct--it's the value of the cell serving as the column header.