'Recently Added' ARAM Battle Boost is not unlocking a skin for all team members in Alpha Client

I got Syndra in ARAM and a skin didn't unlock for me when my friend Battle Boosted. I know I have all the Syndra skins besides Snowday so obviously Snowday is what I should have gotten. But it was still locked. Another person we queued with didn't get a skin unlocked either, but we were the only ones (3/5 did get a skin unlocked).

has anyone else noticed this?

E: FWIW, I assume that I am getting a skin unlocked that I already own, but it could be anything.