These style pages are character bound and cannot be put into the bank, at least that's how it works on console (can't speak for PC). It's hard to overlook or misplace them. They also show up prominently when looting so people going for it most likely will figure out when it drops. Or when it dropped, since the event is over on console by now.Not to be simplistic, but have you checked your inventory carefully? Maybe put it in the bank by accident...