Guild Wars 2

Name: Jam the Bam
Story: Human, Vigil
Mission: The lions arch sewers (Sorry can’t remember actual name)

When fighting underwater in the sewers, at the first bunch of barracudas and jellyfish, there is a straight horizontal tunnel with a right turn at the end.
First of all where you are at the bottom of the vertical shaft the walls will allow both the monsters and the Vigil warmaster who accompanies you to pass through the wall and get stuck, I think it was at the bottom, on the side furthest from the long corridor. This bit can screw up the fight.
It gets worse at the right turn at the end of the corridor, the characters can pass through the wall both to the left of the turn and at the bottom just after. This means that they become obstructed so you cannot fight monsters and the warmaster gets stuck and dies behind a wall.
Often the monsters will go invulnerable and reset at the same time.
This also happens with the undead scout (the final fight of the mission), It spent 80% of the fight invulnerable, I’m assuming this is not meant to happen, there did not seem to be any special skill or anything it was using, I just couldn’t hurt it until it moved a bit.

I have completed the mission but it was frustrating, please take a close look at the wall joins.