The Quick Account Switch, to my understanding, is to allow you to log in to another account without having to go through the whole logout-login process. However, if you are already logged in to an account, and use the quick account switch to access another account without first logging out of the account you originially logged into, the new login will be ignored and you will stay logged into the originially logged into account.
Hopefully that made sense. Please fix as soon as possible. Thanks.