EDIT: Solved. Leaving it in case somebody else has the same problem. The Wisper quest can now be started on the Io map. My friend and I have been trying to start the Wisper of the Worm quest. We start the public event on Io (Taken Blight) in the Lost Oasis, then search all three locations for the hidden Taken boss that appears. We are always able to find it (either Ta'aurc in the caves, Drevis in the rocky ravine, or Urzoc on the cliff) and kill it long before the public event ends. We know the exact spot the portal is supposed to open, but it never does. Even tried waiting until the weekend to do it, since that's what you used to have to do it. Again, the hidden boss is found and killed, no portal. What are we doing wrong?