Returning anything from controller method ends up as a blank page

I have a controller method I use to redirect users after log in or log out.

The method works fine on log in however on log out I always end up with blank page and 302 Found, although it's supposed to return a view and not a redirect response.

Returning even a string or simply 1, ends up in a blank page. On the other hand if I just do die() it redirects to home page.

There's no trace of an error neither in lumen.log or server's error log.