Fencer: i always use brainking.com ... it also gave me the bad sites

when i go to brainking.com i arrive at the login page .. no problem yet .. then i enter my username and password and login .. then the bad site will show

(it even showed a site which avg told me to contain a virus (or 3))

it doesnt happen to me the second time i go to brainking.com though

(maybe i am not logged in yet when i click on login .. so the site will show .. the next time when i enter the site via brainking.com it recognizes my cookie and doesnt show the bad sites?)