I have two identical menu items:
RSVP here > that goes to node/123 (for anonymous users)
RSVP here > civirm/event?12 (or similar) (for authenticated users).
The second shows up properly for authenticated users, however nothing shows up for anonymous users.
Also, not sure if this is related, but both show up for Administrator (under 5.x) this worked right for all three cases.