So, here’s the deal: the nice, light green preview arrow you get on the actor is only for the simple link. If you’re using the smartlink, it’s a lie. If you try to use that preview, then you’ll override the smart link with a simple link, which won’t fire the event.
The solution is to ignore that light green arrow completely and just mess with the relative locations in the smart link settings until the nav mesh preview gives you a chunky, dark green arrow showing where the link has kicked in.
I guess I should submit a ticket to get the UI fixed so it’s not so misleading.
Note that I’m using 4.16 for this.