XSSFFont CloneStyleFrom is linking two fonts instead of creating a copy

[igorjrr]

XSSFFont fontToBeApplied = (XSSFFont)Workbook.CreateFont();
fontToBeApplied.CloneStyleFrom(writableColumn.DefaultCellFont);

When doing
fontToBeApplied.IsBold = true;

The writableColumn.DefaultCellFont.IsBold is also set to True.

[igorjrr]

Not only fonts, but XSSFCellStyle as well. Cloning a style, immediately modifying the border in the cloned style (even before applying it to a Cell) is also modifying the border in the original style.