Unlocks in waypoint

So I was looking at waypoint on my iPad and I wanted to watch the terminals from halo 4. Knowing I have them all I think I should have no worries until I scroll past my campaign stats that say I have only have 6/7 so I’m thinking ok that’s weird but I scroll further down and see I have 7 videos under the terminals for halo 4 and that there is a locked video which is called cryptum. With a small amount of research I find that’s the last terminal name so I guess I want to know where this extra video came from and how did I not unlock cryptum since I have every achievement one of which to unlock every terminal.
Thanks to anyone who helps

Odd. It should be there if you’ve activated and got the achievement for all of them.

If you’re re-doing the campaign on a higher difficulty than you did previously. They may relock. As I unlocked all of them but am slowly doing Legendary solo. Whereas on my waypoint despite me having the achievement, I only have three of the eight terminals unlocked.

I’d suggest redoing the level and get the terminal. Then finish it off. Just load up mission eight and choose rally point bravo.

The location if you forgot where it is, is found here: Terminal 7 Location (Mission 8, Unlocks Cryptum Video) - IGN

If that doesn’t work. I would suggest contacting a monitor or staff member of the issue.