Comment 6 for bug 353356

Observing same issue on Ubuntu 16.04 (after upgrading from 14.04 where same problem was appearing).

I consider that this effect is also there if you lock the screen manually.
Same workaround works:

- (lock screen manually; re-login says "wrong password"
- try to login as another user with wrong password
- after error, switch back to your user
- now login works