Halo 4 Composer game ending glitch? MCC

So I’m playing through Halo 4 again on Legendary couch Co-op with my wife. We are on the 7th mission, Composer. When we get to the room with the 2 hunters in the lab we kill them. Typically a mix of her shooting the DNR from across the room to get their attention and me sticking a sticky grenade to their backs. When they die nothing happens. I’ve been searching for an answer and I’ve only seen threads were people never follow up. At first I just thought, this sucks, guess we will restart. Well we have now done it 3 times and it has failed to open the door to the next area each time. We have accessed all of the data logs in the room, we have ended the fight with all the scientists dead, and sometimes a few are alive, we reset the xbox and started over each time, once we even unplugged it before restarting the level.

After 3 times in a row of having this issue I’m starting to think we are skipping something before going into the room, but can not figure out what. The light on the door never turns green, and cortana never freaks out and opens the door. (I’ve watched video’s of how its supposed to look)

Edit: I should mention that this is the MCC on Xbox One

Bump:

I’ve played twice more again reset my XB1 each time by unplugging it completely. I played from the previous level once, Instead of selecting resume game I selected it from the Level selection screen, still nothing. Any help would be appreciated.

googling pulls up nothing of value, just a million wikis that tag a bunch of words to help pull in clicks. This is really frustrating.

Mcc is broken, but maybe I could help you later today through co-op? Me and my friends beat the level with no problem.

Btw, this should be in the mcc section, no one really reads the halo 4 section anymore.