As the title indicates, I'm not earning any Vestiges of Dread when participating in the Nightmare events, patrols or the like. I've double checked my inventory (link) and it's 17/50 so it's not full. I've also gone through and done as many quests that I might have missed in case there's some kind of pre-requisite to earning them but no luck. Is there something I'm missing or is this a known bug?