The default code that renders the HTML for the product list for an invoice renders too many table cells in the header and footer rows if the renderDiscount flag is false. The lines:

builder.Append(" <thead><tr><th colspan=\"6\" class=\"headerBorder\"> </tr><tr>");
builder.Append(" <td colspan=\"6\" class=\"bottomBorder\"> ");

should both replace the string part: \"6\"

with \"" + (5 + (renderDiscount ? 1 : 0)) + "\"

Example: builder.Append(" <td colspan=\"" + (5 + (renderDiscount ? 1 : 0)) + "\" class=\"bottomBorder\"> ");


A minor bug, but I thought I'd mention it so I don't have to fix it again for my sites in the future. Besides, HTML e-mail clients are horrible with rendering even valid HTML, let alone HTML that isn't quite perfect.