When impersonating another user as an admin, the "Stop impersonating" button takes me to a screen where I can either click "Login using Stack Exchange" or type my password. Since I always log in using Stack Exhange, I don't even have a password; but clicking that button doesn't take me back to my own account. In fact, it redirects back to the start page and I see the familiar "you are already logged in" which I always seem to get ... but the user dropdown on the top right still shows the impersonated user's name.