This issue is reproducible with Aspose.Cells 188.8.131.52.
When using the Aspose.Cells.Workbook.Save method to save the workbook as a PDF, the output PDF contains invalid numeric formatting when the following conditions exist:
1) A cell is formatted as a number, with negative numbers displayed as red and enclosed in parentheses
2) The formatted cell contains a formula that references a cell that contains a negative number AND is hidden.
Under these conditions, the cell displays with a negative sign instead of being enclosed in parentheses. For example, as -2000000 instead of (2000000).
This issue is reproducible with the attached file.