Tooltips for several user show simultaneously in Safari

Precondition
Logout on forum if you are logged in

Steps to reproduce:

1. Open section page (http://qa.jtalks.org/jcommune/sections/1) , click on 1 user
2. Login with invalid data
3. Click Back 2 times (to see section page again)
4. click on 2 user (don't try to login)
5. Click Back again
6. see 2 not hided description and on moving on users see 3

Actuall result: several tooltips are shown simultaneously
Expected result: just 1 tooltip can be shown, on mouseover the user name