Are Halo 4 Achievements Completely Broken Now?

Just finished completing the level Forerunner on the XBoxOne’s Master Chief Collection on Solo Legendary. Watching the cut-scene begin for the next mission, I continued watching the bottom of the screen for my “Forerunner” achievement. No such luck. From the menu (see screenshot #1 linked below), I can see the Difficulty Completed Badge clearly shows Solo Legendary, but the achievement did not unlock, nor did the progress update for the Lone Wolf Legend or The Legend of 117, both still say 2/8 complete. Check the website here and…no such luck, it looks as though I’ve never completed the mission (see screenshot #2).

I did complete the mission with 2 skulls on, same as I did the 2 previous missions, the skulls being Grunt Birthday Party and IWHBYD, both of which have a x1 scoring, so I’m pretty sure that’s not the issue here.

Also, I did complete the mission over the course of 2 days, played most of the mission yesterday, picked up from a checkpoint today and finished it. That shouldn’t be a problem, I’d think, but it’s about the only guess I’ve got. Can anybody help?

#1: What it shows on the xbox one -
#2: What it shows on the waypoint website -