I was logged in and decided to log out to switch to a different account. I pressed the logout and saw a “you have been successfully logged out page”. Then I decided to go just to my index drone page (http://drone.example.com) but then I am immediately logged in as I was before, just like I did not press the “log out” button.
Technically you pressed on logout button but the github/gitlab/other apps oauth token is still associated with the drone server and that’s the reason you are still logged in. If you want to log out, you have to logout from your github/gitlab/other app interface and that destroys the session on drone server.