除非在LibreOffice中打开+保存文件，否则电子表格阅读器无法检测填充颜色

I'm using the RubyXL gem to read background colours of cells of an xlsx spreadsheet generated in Excel. This works fine if the file is opened or saved in LibreOffice. The fill colours are all detected as white (I'm using the RubyXL gem to read background col