Session class is not setting the ci_session cookie in webkit browsers

[eluser]ammonkc[/eluser]
I have a site using CI 1.7.3. The session class is not setting the ci_session cookie at all. But this only happens in webkit based browsers (Safari/Chrome), the session is properly set in FireFox. I'm using Ion_auth library for authentication. But Ion_auth just uses the built-in codeigniter session class. The only cookies that get saved are ones that are set with the set_cookie() helper. Is this a bug in the session class?