If it helps, I had this quest “bug” out on me the first time I tried it as well. Previously, I came up with Fear of Failure, Fixing the Blame, and Marshaling the Truth, but I doubt that matters.
My problem is that when the time came to Retake the Docks at the end of the mission, I ran out through the gate (after killing the first 4 Knights), and down the ramp directly in front of me (sort of to the left maybe). My NPC allies got butchered, and I was left fighting unending waves by myself.
The second time I tried it, after killing those first four Knights, I followed the larger mass of NPCs that went through the gate, and then to the right, and down that ramp. The mission then proceeded and finished exactly like I would have expected.