I have a custom page template that I am trying to use on my WP site (version 4.9). The folder structure where I am placing my page templates are as follows.
When all of the template files are placed up one level in theme-root/landing I can see the template in the page attributes box on the admin screen when editing the page. When it is placed inside the template-name folder it doesn't show up. I have a plugin to clear the file cache so the problem isn't from the caching of files. It is structured this way because the site uses multiple page templates.