3rd to last step you hail Terro Kai and a Shimmering Presence is supposed to spawn but doesnt. Next step you are supposed to give the ring to the Shimmering Presence but giving it to Terro Kai instead does work.
This one has seemed buggy even after the hot fix. After dropping invis and hailing him, he had one additional text to click, which spawns the presence, but I've seen it delay several seconds before spawning (and have, as a result, seen it spawn about a dozen of them once my impatience caught up).
Just done this, a shimmering presence never spawned, handing in to the kitty worked. Chatting about this in guild it seems some can see it and some can't, same bug as in Brother Island with quest NPCs? Maybe just change the quest text and be done with it.
The second post has the solution, you need to be visible before using the keyword. If you use the keyword while invis, just drop invis then hail and use the keyword again to get the presence.