Hmmm, but that's because you're logged in, to render the admin-bar, no?
I indeed see this call on my site when logged in;
http://fonts.googleapis.com/css?family=Open+Sans%3A300italic%2C400italic%2C600italic%2C300%2C400%2C600&subset=latin%2Clatin-ext&ver=4.2.2
As this is external CSS, Autoptimize does not touch this.
When not logged in, there's no such request (me happy).
frank