Achievement glitch - unlocked but not counted

Last night I went into Halo 2 campaign to check which levels I had completed on which difficulty settings. A slew of a dozen achievements popped up all at once. I had not earned any of them. Of the twelve that popped, only three added to my gamerscore, but all show as unlocked (down to the same minute).

Now, I have played all of these levels, and “beaten” them - with non-scoring skulls active. So at the time of completion, these achievements were disabled because of skulls used, and something has since gone wrong where the game no longer correctly locks these achievements based upon that stipulation.

However, in some incredibly strange manner, a secondary glitch has occurred because of/following the first set. Before this event, I had seen my gamerscore blip up on the homescreen, and noted that it was 41,110. I thought it was a fun number, and it stayed in my mind for a bit. Now, I don’t recall if that was after the last legitimate achievement I had earned or not, but it’s enough to realize something has gone wrong. When these all popped unexpectedly I was curious what all I had earned and checked. 12 achievements worth a total of 180G. My gamerscore rose to it’s current 41,160. It should have increased by 180G, but actually increased by only 50G.

I have no way of knowing for sure which were added to my gamerscore, but I suspect the first three. It makes sense that the system would begin correctly, and then only because of the sheer size of the onslaught get confused. The first three to unlock were worth 50G together (30,10,10). The final three add to 40G, and the fifth would push that over to 70G so it wasn’t counting properly by that end.

Just to be perfectly sure I’m not imagining things, I counted all the achievements for MCC (thank you spreadsheets ignoring text values in the sum function).

Earned | Remaining
Listed: 2755G, 324 Achievements | 2245G, 176 Achievements
Actual: 2885G, 324 Achievements | 2115G, 167 Achievements
Off by: 130G, 0 Achievements | 130G, 9 Achievements

TL;DR: Achievements earned in Halo: The Master Chief Collection when unlocked may or may not add to one’s gamerscore.

List of unmerited but “earned”, unlocked but (partially) uncounted achievements from this glitch:

> Herald of the Reclamation
> Complete all campaigns on Easy difficulty.
> Unlocked 14 hours ago
> 20
> Big Green Style
> Halo 2: Complete every level of the game on Easy difficulty.
> Unlocked 14 hours ago
> 10
> Tighten Up The Graphics
> Halo 2: Complete every level of Halo 2 having seen it in both classic and remastered mode.
> Unlocked 14 hours ago
> 10
> Legendary Anniversary
> Halo 2: Complete every level of the game on Legendary difficulty.
> Unlocked 14 hours ago
> 30
> Hero
> Halo 2: Complete every level of the game on Heroic difficulty.
> Unlocked 14 hours ago
> 20
> Warrior
> Halo 2: Complete every level of the game on Normal difficulty.
> Unlocked 14 hours ago
> 10
> The Great Journey
> Halo 2: Complete The Great Journey.
> Unlocked 14 hours ago
> 10
> High Charity
> Halo 2: Complete High Charity.
> Unlocked 14 hours ago
> 10
> Uprising
> Halo 2: Complete Uprising.
> Unlocked 14 hours ago
> 10
> Gravemind
> Halo 2: Complete Gravemind.
> Unlocked 14 hours ago
> 10
> Quarantine Zone
> Halo 2: Complete Quarantine Zone.
> Unlocked 14 hours ago
> 10
> Veteran
> Complete all campaigns on Normal difficulty.
> Unlocked 14 hours ago
> 30

Update: After the next achievement (10G), the score was updated and I’m now only missing 10G. Other achievements after have been added appropriately.

No Easy Way Out - Halo 4: Survive Spartan Miller (Ep.5 Ch.1) of Spartan Ops on Heroic or Legendary. - 10G
Is glitched. As it reads it should not be missable (unless on Easy/Normal) and on my Legendary playthrough it did not unlock.