Older raids, such as Last Wish and King's Fall, are missing the notification if you fail the encounter challenges. Not sure if it is for both sets, but I am positive it doesn't let you know for the one-off encounter challenges. This is incredibly frustrating, especially for triumphs such as 'Which Witch' on Shuro Chi in Last Wish. You have no idea if you are successful or not, until you finish the encounter and pray that the triumph complete notice pops up.