Empty page instead of 404 error when url contains channel slug

Question

I have a website where my client can create entries in a couple of different channels.

Lets take a "news" channel. The url would be: "example.com/news/nameofpage"

Whenever a wrong url is entered manually behind "example.com/news/" (or maybe a wrong filled in link) it won't go to the 404 page but just enters the channel's template and display's an empty page. For everything else the 404 error works but whenever a channels slug is in the url as a first segment it only gives an empty template.

EDIT:

I figured out it happens all the time whenever there is a second segment in the url

Answer 1

As Brad pointed out in the comments on my question I had to take a look in the custom route's defined in the Craft CP. My client tried to make a custom route which looked like this:

This caused for every url containing one "/" to use that template that unfortunately actually was a template that's why it wouldn't give a 404.

Original Comment:

Maybe an .htaccess rewrite rule interfering? Do you have any custom routes defined (in the Craft CP or in config/routes.php)? – Brad Bell