Problem in Dropdown in Bootstrap 4.2.1

Created by: afuno

Bootstrap 4.2.1 / macOS 10.14.2 / Chrome 71.0.3578.98 / Safari 12.0.2

Dropdown works: https://codepen.io/anon/pen/oJZKXW Dropdown doesn't work: https://codepen.io/anon/pen/BvWXNO

Uncaught DOMException: Failed to execute 'querySelector' on 'Document': '/posts' is not a valid selector.

The problem arises due to the presence of the link. In the application there are many places where the link in this place is “just like that”.

I think... it is necessary to fix it not on my side. What do you think?