Yesterday I had a playthrough of all the chapters in the new episode. Upon activating all the guns on the last level (the one that's modelled after Complex) all the NPCs/Covenant were invisible. All you could see were their weapon and the weapons were literally dragging on the floor, and I was dying from invisible bullets. At first I thought they were on the floor below me and they were glitching through but I quickly noticed that was not the case. This went on for the rest of the mission and occasionally there would be a jackel or a pair of elites that weren't invisible.
Needless to say I still completed the mission but I had to shoot little plasma pistols rolling around on the ground to win. It was like I was playing against possessed weapons.
EDIT: The title should read Episode 3, Chapter 2