Exceljs : ‘We found a problem with some content in “file.xlsx”(…)’

I’m having some issue with an Exceljs generated xlsx file. I’ve created csv files in my project for a while without any problem. But now I’m creating an xlsx file and, while I can open it clean on my Ubuntu/LibreOffice Calc, there is an error when trying to do the same on Excel (on Windows and IOS all the same).

My file’s name is “export-yyyy-mm-dd.xlsx” with two sheets named “Total” and “Details”, respectively.

Both sheets have a “fake” title line above columns headers. The second file has 13 columns of either string or number data for all my users while the first sheet aggregates those data in 6 number columns, with just one line under the headers.

It is that first sheet one line of data that is missing when opening the file with Excel.

What I’ve tried so far :

  • move plain numeric values from string format to number format
  • move the one percentage cell from string to number format too
  • update my Exceljs package (from 3.9 to 4.4)

I’m out of new ideas right now so : what might be causing this problem ?