I've worked on collecting giants' emblems lately, and arriving at some shrines, ready to donate, I often discovered i had already gained the emblem.
Just once, I saw the notification "you got Spriggan emblem, go to a shrine to collect it". I missed all of the others.
I don't know if it's a bug (maybe there's been no notification at all) or if I just didn't pay attention to them, but I think the notification should be clearer, more visible, especially for the first one.
Maybe a pop-up in the middle of the screen, like for quests and skills, at least for the first one. Maybe it happens too often when you're at high levels ans you don't want to be bothered with emblems pop-up while playing... But the first shouldn't be missable like they are right now.