Reproduce:
1) Insure that auto-populate passwords is enabled
2) Open a tab, say google.com
3) Open a second tab with a password field, say GameFAQs.com
4) Before GameFAQs.com is done loading (and before the prompt appears), switch to the first tab.
5) The password created will be for google.com not for GameFAQs.com
This is most noticable if you have several accounts for google.com, as it will ask you to choose one of them. Also note that the password is still populated into GameFAQs.com.
BTW- Found in all versions of 0.6