I really don't understand why my (quite simple!) formula won't get calculated:

        var logfile = new System.IO.FileInfo(@"C:\EpplusLogFile.txt");
        sheet.Workbook.FormulaParserManager.AttachLogger(logfile);
        var mycell = sheet.Cells[1, 1];
        mycell.Formula = "1+1";
        mycell.Calculate();
        Console.WriteLine($"{mycell.Address} {mycell.Formula} {mycell.Value}");
        sheet.Workbook.FormulaParserManager.DetachLogger();
        Console.ReadLine();

1. Console displays: A1 1+1 #VALUE!
2. Log file is not created (but no exception is raised)

I'm using EPPlus 5.8.5

Additionally:

        var cell1 = sheet.Cells[1, 1];
        cell1.Value = 999;
        var cell2 = sheet.Cells[1, 2];
        cell2.Formula = "A1";
        cell2.Calculate();
        Console.WriteLine($"{cell2.Address} {cell2.Formula} {cell2.Value}");

Console displays: B1 A1 999 as it's supposed to. But:

        var cell1 = sheet.Cells[1, 1];
        cell1.Value = 999;
        var cell2 = sheet.Cells[1, 2];
        cell2.Formula = "A1+1";
        cell2.Calculate();
        Console.WriteLine($"{cell2.Address} {cell2.Formula} {cell2.Value}");

And console displays: B1 A1+1 #VALUE!

To me, this makes no sense.