File restriction not working?

Hi, I am trying to restrict user access to files but I can’t make it to work.
I have created a new user group (Group1) with default options and I have uploaded pdf file and set its Access to Group1.
In Media file list I can see that this file is assigned to Group1. When I log out I can still access file at localhost/website/wp-content/uploads/2017/12/pdf.pdf

Am I missing something? I have installed latest v2.1.10 and in uploads folder I can see that there is .htaccess files with rewrite rules.