Gifting Center not displaying all skins

A friend is trying to gift me a few skins, but they don't show up in the gifting center for him to select. e.g. he's trying to gift me Arcade Ahri, but none of the Ahri skins show up for him to select. Neither of us own the skin and I own the champion Ahri. (Both of us own Blitzcrank but none of the Blitzcrank skins show up for him.)