Secret Stash Mastery Not Applied

I was in game already and bought potions, thinking they would be biscuits. They weren't. So I logged on to lolnexus to see what my runes were and there it was, 12/17/0... It was really bizarre. After the game I checked my rune pages and sure enough, it was checked. I just didn't get it during the game. As you can see everyone else had full mastery page numbers.