Minecon 2012 cape is not always showing up on the character

What I expected to happen was:
The cape cape should appear on my character

What actually happened was:
There is no cape on my character

Steps to Reproduce:
1.Login
2.Start playing singleplayer or join a server
3.Most of the time there will be no cape on my character

Please note this happens in every version of minecraft which support capes

Here is my thread on Minecraft-Forums: http://www.minecraftforum.net/topic/1691940-minecon-2012-cape-not-always-showing-up/ (apparently I'm not the only one)