Quaratine Zone bugged?

Yesterday, I was attempting to do the par score achievement for the level Quarantine Zone in Halo 2, along with my friend. We would load up the level normally, and there would be no problems, until we got to the remains of the Sentinel Constructor Factory. The first checkpoint we get in the factory, my friend and I seem to be separated. In my game, my friend is walking into walls, but is saying that he is progressing though the mission like normal. In his game, the same problem persists, while I try to progress. When my friend got to the cutscene before the gondola, I wasn’t able to see it. In both our games, when we tried to get further into the mission, our character in their game would teleport them back to a earlier loading zone, if they walked into it. This made the mission unplayable, and we stopped playing. I hope that this problem can be fixed.

same. im hoping its fixed now.