apparently, QNetworkCookie strips quotes from cookies, which should not be done for RFC-2109-style cookies. E.g. logging in to LinkedIn does not work (-> https://bugs.webkit.org/show_bug.cgi?id=49444).

As a side note, there is a discussion going on currently about whether quotes in cookies should be treated special or not (-> https://www.ietf.org/mailman/listinfo/http-state).