While leveling 2 mentees after today's maintenance, I've noticed the bug is still there, and even got worse, since you'll get stuck in the 3rd room, right before the central square.
But you can still finish it, by the same method I stated 2 posts ago. After talking to the grail, if you can't see the 2 npc's, use "/target mysterious" first and talk to him, then use "/target kain" and talk to him.
And I'm still hoping the bug will get fixed. For regular players, it's easy to overcome this issue. But new players, can't advance in the game after hitting 85. If you don't want/need income from new players, make the servers private for top contributors...