It is near the end of the feros mission, not the end of the first game , just came through this section again yesterday. I would say if you just play through the main missions you can get there in about 5 hours.I've played through Mass Effect Series 3x times. I recall everything. I'm surprised they managed to get to the end game so quickly and measured all 3 titles.
ANyway on what you see there, it's literally not rendering anything. It's probably a poor time for the high level API to setup a new scene or something and it just has a bigger problem with moving larger buffers around to do it. Rendering workload problems don't dip all the way down and come back all the way smooth. Workload problems hover around the same area when the limit is hit. I'm fairly positive what you're looking at is a memory management problem.
But yeah the black screen might be the issue here. But those graphs are also not always at the correct position lined up with the video.