Hello, I know other people had this issue as I saw tweets about it before Solstice ended, but I haven't seen it mentioned in known issues or the triumph section of known issues. Myself and others included where never awarded the Solstice triumph for obtaining all 3 sets of armour on their characters, in my case it acknowledged my hunter and titan armour but not my warlock despite completing it, now the event is over of course and this triumph is gone. I hope there's a fix coming for this that will award it to players who completed this objective during the event.