WP User Manager - Redirect the login and register pages for logged in users to the account page

wpum_redirect_login_page_for_logged_in_users.php

<?php

add_action( 'template_redirect', 'wpum_logged_in_login_redirect' );
function wpum_logged_in_login_redirect() {
   if ( ! is_user_logged_in() ) {
      return;
   }

   if ( is_page( wpum_get_core_page_id( 'login' ) ) || is_page( wpum_get_core_page_id( 'register' ) ) ) {
      wp_redirect( get_permalink( wpum_get_core_page_id( 'account' ) ) );
      exit;
   }
}