The (Hard) denomination on some of those earlier primals.
Like, I understand that they're meant to communicate a step-up in terms of difficulty and that they're 8-man instead of 4-man but...it still just bugs me a bit cause Ifrit, Garuda, and Titan have base/normal 4-man versions of the trials, but then with, say, Leviathan and Ramuh you have (Hard) and (Extreme).