При добавлении записи в типе контента выдает 500 ошибку

Warning: Illegal string offset 'id' in D:\OpenServer\domains\city\system\fields\user.php on line 17
 
Warning: Illegal string offset 'nickname' in D:\OpenServer\domains\city\system\fields\user.php on line 17
 
Warning: Cannot modify header information - headers already sent by (output started at D:\OpenServer\domains\city\system\fields\user.php:17) in D:\OpenServer\domains\city\system\core\controller.php on line 738
 
Warning: Cannot modify header information - headers already sent by (output started at D:\OpenServer\domains\city\system\fields\user.php:17) in D:\OpenServer\domains\city\system\core\controller.php on line 740

class fieldUser extends cmsFormField {
 
    public $title   = LANG_PARSER_USER;
    public $is_public = false;
    public $sql     = 'varchar(255) NULL DEFAULT NULL';
    public $filter_type = 'int';
    public $filter_hint = LANG_PARSER_USER_FILTER_HINT;
	public $allow_index = false;
 
    public function getInput($value) {
        return html_input('text', $this->name, $value);
    }
 
    public function parse($value){
       return '<a href="'.href_to('users', $value['id']).'">'.htmlspecialchars($value['nickname']).'</a>'; // Ругается на эту строку
    }
 
    public function applyFilter($model, $value) {
        $users_model = cmsCore::getModel('users');
        $users = $users_model->filterLike('nickname', "%{$value}%")->getUsers();
        if (!$users){
            return $model->filterIsNull($this->name . '_id');
        } else {
            $users_ids = array_collection_to_list($users, 'id', 'id');
            return $model->filterIn($this->name . '_id', $users_ids);
        }
 
    }
 
}