Wrong User Image Display - Weird Twig Cache?
When you add data from the current user you also have to add this cache context:

$variables['#cache']['contexts'][] = 'user';


You can also add the cache dependencies of the user, file and image style. Then modifying one of these entities will be effective immediately, see https://www.drupal.org/docs/8/api/render-api/cacheability-of-render-arrays