"Source of Orr" is broken
i have had this problem are you by any chance a thief or mesmer?
it seems that he is bugged when he loses trahearne as a target. Me (as a thief) used shadow refuge on him since thats the only thing i can do to heal someone else a bit. then he glitched for me. third try i did not do this and it worked fine for me.
Same trouble here he goes to the middle and becomes INVULNERABLE ! Yes I am a mesmer but nothing I do can get him out of the pool or invulnerable state!
My character is a ranger and I had many problems with this bit of the story line. What I figured out was that when the eye goes to teleport, STOP attacking it and pull your pet/minions back as well. After it has teleported and started its new attack sequence, feel free to hit it. When ever I hit it immediately after it teleported, it would not start its next attack sequence and proceeded to remain immune to damage (glitches out.)
Summary, do not immediately attack the eye after it has teleported— give it time to start its next attack sequence.
Also, when it does the exploding energy bubble things, run through the center of them- if you run near a wall and Trahearne gets bumped against a wall, he gets stuck in the wall and it glitches out yet again.