Got this skin from the Xbox Gamepass bundle, so far this seems to be the only skin to be missing. not sure if this is something from the recent patch or not.
With game pass, you only get skins and cosmetics from the past 3 seasons for free, no longer. The Sakura skin for Kiriko come out at around February time I believe, which was 4 seasons ago which is why it is missing, you’d have to wait for it to come back in store I guess to get it permanently