Yes. I say surprising, because traditionally web servers redirect from the bare name of a directory to the equivalent with a slash at the end. This then either redirects to the index.html or just serves it directly. In Apache, these are both handled by mod_dir: https://httpd.apache.org/docs/2.4/mod/mod_dir.html. They are using Varnish in front of the web server, and I don't know if they want this behavior or not.