On their website, they say everyone does. Since everyone has been delayed from the very beginning of the cycle (earliest secondaries didn't go out until 7/14) there is no way to know for certain that this really happens, but they also have no reason to lie about it. Of course, I'm sure the secondary review for the 3.9/518 applicant is a little less holistic than for the 3.5/512 one, but, still....
I think it's a little premature to worry, since they reportedly already have over 4,000 applications to work through. OTOH, and I don't mean to sound glib here, if you are at the low end of their stat range and they don't send you a secondary, you really should send them a thank you note, because all they are doing is saving you time and money without changing your outcome. It's honestly a kindness I wish all schools would extend to us, as opposed to the common practice of having us write essays, taking our money, and then ghosting us for months on end before rejecting us.
Check your spam filter and then try to take it easy for another few weeks, focusing on schools that are focusing on you. Good luck!!!