PDO::execute not working on UPDATE but works fine on INSERT

Question

I am trying to update a column but it is not working and displays no error. It works if on INSERT.

• var_dump($data); contains the correct elements
• var_dump($req); contains the correct elments
• Anything after $req->execute($data); is not displayed unless execute() is commented out.
• var_dump($req->execute($data)); doesn't return anything.

$this->dbLog is my PDO connection.

  public function updateNotification($id, $user)
  {
    $data = array(
        'id'   => intval($id),
        'user' => $user,
    );

    $sql = "UPDATE db.user_alerts
            SET `clicked` = 1
            WHERE TRUE
            AND id = :id
            AND user_name = :user
            ";

    $req = $this->dbLog->prepare($sql);

    $req->execute($data);
  }

I also have a column with a default value of CURRENT_TIMESTAMP, do you think it can be the cause of the problem ?

Thank you in advance for your help.