I have detected an extremely annoying bug in Safari, today.

There is a bug in cookie management. If a page sets a persistent cookie (expiry date is far enough in the future) this cookie must be kept at the re-launch of the browser. This does not always happen in Safari.

Cookies are only persisted if you close the window/tab that set cookie before quitting Safari. If you quit Safari without expliciutely closing the tab that set cookie - forget about it.

Sample scenario: I fire-up Safari and go to http://www.motime.com, I log in there, work for a while and then do File->Quit without closing the tab/window where I used to work with the page. The cookie will be lost!

If I close the tab first, and then exit Safari - cookie will be persisted.

I submitted a bug report to Apple but in my past experience their Safari support team is not extremely responsive so, I do not have too high hopes on quick fix, so far.