Discourse thread: https://discourse.gohugo.io/t/section-index-md-page-isnt-being-created/10627
Sample project: https://github.com/ChrisTucker2000/hugorepro

Steps to reproduce:

1. Create a section index page, e.g. /content/cats/_index.md.
2. Create an appropriate template file, e.g. /themes/mytheme/layouts/_default/list.html.
3. Set uglyURLs = true in /config.toml.
4. Build the website with hugo.

Expected result:

• The page should be created as /public/cats/index.html.

Actual result:

• The page is created as /public/cats.html.

Additional information:

There is a Hugo documentation page discussing how uglyURLs works: https://gohugo.io/content-management/urls/#ugly-urls
It clearly says on this page that /content/about/_index.md will map to https://example.com/about/ with uglyURLs = false and https://example.com/about/index.html with uglyURLs = true (so basically the same output file).
This is the behavior that I expect, but it is not the behavior I'm getting.

Therefore this is either a bug in Hugo itself, or a mistake in the documentation. I hope it's the former, because this behavior seems totally bizarre and insane to me.