You may remove the private data from your Excel file(s) or you can also make this topic a Private Topic, then only you or we will be able to access your files.
You may also create the template Excel file(s) manually using Microsoft Excel to show the issue. We need your sample console application project replicating the issue to investigate and fix this issue.
Please also note, if you have formulas, then you must calculate the formula using Workbook.calculateFormula() method. Please see this article for more help.