Today's update contains several security improvements.
One of the improvements is about how the password/username change is handled from now:
Changing your password
If you change your password, you will be immediately logged out on all devices and be required to re-login.
Until now you were required to re-login on other devices only when you restarted the browser.
Changing your username
If you change your username, you will be also logged out on all devices and be required to re-login.
Until now the username was automatically updated on other devices, no re-login was required.
