SheetJs CONCAT resulting in =@CONCAT

I’m using SheetJS CE

package.json

"xlsx": "^0.18.5"

I can do SUM just fine, but with CONCAT, when I downloaded the xlsx file, the formulae turn out to be @CONCAT() and cause error to the field.

  const rows = [
    {
      name: 'George Washington',
      birthday: 'March',
      age: 10,
      month: 20,
      formula1: { t: 's', f: 'CONCAT("Sheet", "JS")' },
      formula2: { f: 'SUM(C2, D2)' },
    },
    {
      name: 'John Adams',
      birthday: 'Feb',
      age: 20,
      month: 5,
      formula1: { t: 's', f: 'CONCAT(A3, B3)' },
      formula2: { f: 'SUM(C3, D3)' },
    },
  ];

as you can see on the screenshot, the formulae becomes =@CONCAT, instead of =CONCAT()