Guild Wars 2

The fifth attempt worked, although only because of another bug, i think. While fighting the drake in the first vertical tunnel, Forgal clipped through the wall and suddenly the missing guardsmen objective was cleared and i was told to continue investigating the sewers. I figured i could rush to the green guy now, did that, but died in the fight. When i respawned at the checkpoint, the green guy clipped through the floor and attacked me outside. Forgal clipped along and we killed him, but apparently there was one shark left, because the kill undead objective didn’t clear. So i went down into the cave again, to find one of the sharks clipping his head through the wall. Killed him, and the final objective cleared.
I don’t want to complain or anything, but guys, this quest is one super buggy mess.

I tried the quest three times now, without success. The first time, after the battle against the green guy, Forgal disappeared and the quest tracker was stuck at investigate under broken grate. Second time, he disappeared and the quest tracker got stuck at search sewers for guardsmen. The first two times i killed everything on the way to the green guy, the third time i just rushed through, then Forgal popped up next to him, we killed him, Forgal swam away, I followed him (right tunnel after coming out of the cave), he said this is a dead end and won’t lead us anywhere, but kept on swimming out of the mission area, while the quest tracker was stuck at the guardsmen again.