Fiora Ult

When i was playing my last game as Fiora i was also versing a Fiora, post level six nothing was wrong, but once we reached level six on several occasions after she had ult-ed me i did what most would do as well, ult back, but when ever i did my ult would go on cool down and nothing would happen, it wouldn't show the Vitals, even though it removed my previous Vital Location. I don't know if it just happened to be me but it happened at least 3 times in the game.