For Activities - Dark Below, are you sure it's not Will of Crota. When I beat that strike (not as a Nightfall or heroic since it didn't show up then), I got a grimoire card pop up saying I unlocked the Will of Crota card but I don't see it in my Grimoire.
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I've played Will of Crota in the 26 playlist a ton of times, and I also got that list by cross-referencing my Grimoire with DestinyDB's list. It's definitely The Wakening card.