So, I finally decided to let my curiosity get the better of me, and purchase a Birthday Cake. I summoned it at GoB outside of Goddard, and the after a few seconds, it gave me a 20 min buff. Then, my friends showed up, and they all got the buff as well, except my clan leader. He tried relogging and just about everything he could do, but without any luck.
My 20 minute buff ran out, and I didn't get a new vitality buff either.
Here is the screenshot:
How exactly is it supposed to function? Are there rules or tricks for getting it to work properly?