Header text appear as property value in the CUSTOMTOOLS Excel Report output file and the values also goes out of the expected bounds of the Excel report table (Picture 1).
This issue is fixed in the CUSTOMTOOLS 2017 SP1 version.
With a CUSTOMTOOLS version older than 2017 SP1, you can fix the issue using the following instructions. Before you start, make sure that you do not have any SOLIDWORKS or CUSTOMTOOLS instances already running.
excelApp_.CutCopyMode = (Excel.XlCutCopyMode)0;
Once compiled the changed script, you can close the CUSTOMTOOLS Adminstration. The CUSTOMTOOLS Excel Reporting feature should now work properly again.