Cannot pick Corki in Team Builder - Join a Team?

I'm not sure what happened. I had just purchased Corki and tried selected him. It allowed me to attempt to create a game and then said that the champion was null. So I tried again, and Corki did not exist anymore. He does exist for Team Builder - Build a Team however, which is the strange part...

I tried logging out and logging in, I tried playing him in a game prior to trying Team Builder again, and he still doesn't exist... Anyone have any idea what may be happening?