Décalage dans les colonnes du fichier csv

$repertoire = '/var/www/test/';
$month= date('m', strtotime('-1 month'));
$year = date('Y', strtotime('-1 month'));
$concatFilename = $year . '-' . $month . '_Import.csv' ;
$concatFile = fopen('./' . $concatFilename, 'w');
$nFichier = 0;
foreach (scandir($repertoire) as $filename) {
   if (substr($filename, 0, 7) == ($year . '-' . $month)) {
       $currentFile = fopen($repertoire . $filename, 'r');
       $nLine = 0;
    while (($data = fgets($currentFile)) !== false) {
           if ($nLine === 0 && $nFichier !== 0) {
               $nLine++;
           } else {
               $data .$nLine = 1;
               fputs($concatFile, $data);
               $nLine++;
           }
       }
       fclose($currentFile);
       $nFichier++;
   }
}
fclose($concatFile);