I found this just now, in some formatting code:
if ((data.TotalPrice - data.TotalCost) < 0) { ApplyToCells(row, cell =>
cell.Style.ForeColor = Color.Red); } ApplyToCells(row, cell =>
cell.Style.ForeColor = Color.Black);
Problem is that it should have been
if ((data.TotalPrice - data.TotalCost) < 0)