Twig cache won't disable
In Drupal 8.4 you have to set the null cache backend for an additional cache bin, so now there are three:

settings.local.php:

$settings['cache']['bins']['render'] = 'cache.backend.null';
$settings['cache']['bins']['page'] = 'cache.backend.null';
$settings['cache']['bins']['dynamic_page_cache'] = 'cache.backend.null';


This is because the cached pages for anonymous users moved to a separate cache bin, see the change record The internal page cache now has a dedicated cache bin.