Hey there! It looks like the Triumph gets awarded even when the Event is not live yet. When looking at your triumphs, you'll notice that the "new" Triumph is in the Revelry category, basically filling a place that is already there. I'd recommend to not turn in the Triumph (if you haven't done so already), but I don't think there will be issues once Guardian Games goes live. A similar issue existed already before the launch of the Tribute Hall, you could get some Triumphs for tributes early, but it didn't affect your progress in any negative way, so I wouldn't worry about it.