Yeah, I can confirm this Bug, I'm Stuck on the same Mission, your 4 away team members fall under the boat in the first second, when you go onto the stoney shore before the gates of Gre'thor nearly all the NPC's Glitch and they teleport under the boat where they die, the Gate operator Does not open the gates due to him stuck under the boat unconscious or something, It's rather dull
The Gates of Gre'thor is still broken. Please Fix the Map.
We did this as a team of 4 (the NPC kept dying as above), and managed to get through it. The boss at the end, and many of the NPCs, also have a tendency to fall through the world making it even weirder.
I recommend holding him in place and tanking him without running around if you're doing it as a group (as much as possible, as you have to keep out of the fire).
I spent some time trying to finish this mission last night - it is possible to get to the final boss, although beating the various enemies because they fall through the floor and die is a big let down.
When I got to the final boss, it wouldn't take damage, and kept falling through the floor and respawning.
One small set of KDF exclusive episodes, at least try fix some of the glaringly obvious problems please.