formula not correct with vba

Hello,
Why does my formula with vba code
Messed up, this code from vba will show on the master sheet on B9 the formula
but Instead of

=SORT

It shows

=@SORT

        ' Initialize formula string
        formulaString = ""
        firstFilter = True

        ' Include filters for existing tables in all worksheets
        For Each ws In ThisWorkbook.Worksheets
            For Each tbl In ws.ListObjects
                If tbl.Name Like "TBL_*" And tbl.Name <> newTableName Then
                    If Not firstFilter Then
                        formulaString = formulaString & ", "
                    End If
                    formulaString = formulaString & "FILTER(" & tbl.Name & ", " & tbl.Name & "[MASTER] = TEXTAFTER(CELL(""filename"", A1), ""]""), """")"
                    firstFilter = False
                End If
            Next tbl
        Next ws

        ' Add the new table to the formula
        If formulaString <> "" Then
            formulaString = "=SORT(VSTACK(" & formulaString & ", FILTER(" & newTableName & ", " & newTableName & "[MASTER] = TEXTAFTER(CELL(""filename"", A1), ""]""), """")), 6, 1, FALSE)"
        Else
            formulaString = "=SORT(FILTER(" & newTableName & ", " & newTableName & "[MASTER] = TEXTAFTER(CELL(""filename"", A1), ""]""), """")), 6, 1, FALSE)"
        End If

        ' Set the formula in cell B9 of the "Master" sheet
        On Error Resume Next
        masterSheet.Range("B9").ClearContents
        masterSheet.Range("B9").Formula = formulaString

Any idea how to solved that?
Thank you