Resending the document to the mail, why?

Question

Yii

Hello everybody! There is a GridView table, a separate button is written to send an automatically generated pdf document to the specified mail. The document arrives in the mail, there are no problems, but it happens that no one presses the send button, and the same document comes to the user again a week later, why this happens I can’t understand, please help.
Code in controller:

public function actionPdf($id)
{
    $model = $this->findModel($id);
    $content = Yii::$app->view->renderFile('@app/views/order/_forma.php', ['model'=>$model]);

    $pdf = new Pdf([
        'mode' => Pdf::MODE_UTF8,
        'format' => Pdf::FORMAT_A4,
        'cssFile' => '@vendor/kartik-v/yii2-mpdf/assets/kv-mpdf-bootstrap.css',
        'orientation' => Pdf::ORIENT_LANDSCAPE, 
        'destination' => Pdf::DEST_BROWSER,
        'content' => $content,
        'options' => ['title' => 'Портал'],
    ]);

    // $fileName = 'list' . md5(time()) . '.pdf';
    $fileName = 'list_' . $model->id . '_ot_' . $model->date . '.pdf';
    $filePath = Yii::getAlias('@app/web/upload/documents/rctp/pdf/' . $fileName);

    $attachment =  $pdf->output($content, $filePath, Pdf::DEST_FILE);

    $result =  Yii::$app->mailer->compose()
        ->setFrom(['[email protected]' => 'Контора'])
        ->setTo($model->email)
        ->setHtmlBody('Текст')
        ->setSubject('Перечень оборудования #' . $model->id . ' от ' . $model->date)
        ->attach($filePath)
        ->send();

    unlink($filePath);

    return $this->redirect(Yii::$app->request->referrer);
}

Submit button code

[
    'label' => '',
    'value' => function($data){
        if($data['email'] == true){
            return Html::a(
            	'<span>', 
            	Url::to(['order/pdf', 'id' => $data->id]), 
            	[
            		'class' => 'glyphicon glyphicon-envelope', 
            		'title' => 'Отправить документ на email ' . $data->email, 
            		'data' => [
                		'confirm' => 'Вы подтверждаете отправку документа пользователю ' . $data->name . ' ' . ($data->email),
                		'method' => 'post',
            		],
            	]);
        }else{
            return '';
        }
    },
    'format' => 'raw',
],