Shortcode creating two pages

I have the following shortcode created.

  function add_contestant_function() { 

      // Create post object

      $num = mt_rand ( 0, 0xffffff ); // created random number
      $idnum = sprintf ( "%06x" , $num ); // formats random number
      $newname = 'PC' . $idnum; // creates new contestant page from random number
      $newpass = 'MMV' . $idnum; // creates new contestant page from random number
      $my_post = array(
        'post_title'    => $newname,
        'post_status'   => 'publish',
        'post_author'   => $newname,
        'post_type'     => 'contestant'
      );
        
      // Insert the post into the database
      wp_insert_post( $my_post );

      ob_start();
      ?>
      <p><b>This is your page ID : <?php echo $newname; ?>
      <p>This is your page PASSWORD : <?php echo $newpass; ?></b>
      <?php
      return ob_get_clean();

  }

  add_shortcode('add_new_contestant', 'add_contestant_function');

When it is added to a page it works as expected except that it creates two pages every time the page is accessed. I am not sure why. Please tell me what other information you may need to help me understand how to fix this.

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