[GAMEPLAY] Nightblade Irelia Skin not available in game

I recently purchased the Nightblade Irelia skin yesterday and have played multiple games with her since then. However, each time I select the Nightblade skin, the pregame loading screen shows Irelia's default skin and she appears with the default skin in game. I've only tested this on Summoner's Rift so far, but it doesn't matter whether it's teambuilder or blind pick; it's always going to revert back to the default Irelia skin.