I have already posted this in the "champion and gameplay" board, but this seems more like a bug to me now, so I'll repost it here:
Just as the title mentions, how is this a thing? As far as I know fiora w parries every single ability in the whole game, why does this go through?
"Fiora's W: Riposte makes Fiora invulnerable (for example like Kayle's ult), and that should block the execution of Pyke's ult.
"Invulnerability and undying effects will still protect the target."
Quote from https://leagueoflegends.wikia.com/wiki/Pyke"
Thanks to Grimmrok for this information.
Example 1: https://imgur.com/3fIHGQb
Example 2: https://imgur.com/VUlHyL0