Weired underline error

[teezz]

Weired underline error

when I generate and open XLSX files with axlsx all text and numbers are underlined by default:

styles.push(@sheet.styles.add_style(:bg_color => cell["fill_color"], :fg_color=>cell["font_color"], :b=>cell["bold"], :i=>cell["italics"], :u=>false,
Does anyone have a clue how to fix that?