The shape outline color is missing

I use this file to copy the sheet and save it to a new file, but the shape outline color is lost.

code:
foreach (Worksheet worksheet in workbook1.Worksheets)
{
Workbook workbook2 = new Workbook();
worksheet.Cells.RemoveFormulas();
workbook2.Worksheets[0].Copy(worksheet);
workbook2.Worksheets[0].Name = worksheet.Name;

                string newPath = Path.Combine(tempDir, worksheet.Name + ".xlsx");

                workbook2.Save(newPath,SaveFormat.Xlsx);
                vs.Add(newPath);
            }

test.zip (51.9 KB)

@victorliao1998,

We found the issue using your template file. We have opened the following new ticket(s) in our internal issue tracking system and will deliver their fixes according to the terms mentioned in Free Support Policies.

Issue ID(s): CELLSNET-52825

You can obtain Paid Support Services if you need support on a priority basis, along with the direct access to our Paid Support management team.