Team Builder Bug

So I just went into a Team Builder with my friend, and we decided to do a Yasuo/Wukong knockup combo. So, I picked Wukong and we started searching for players, and we loaded into the game.

Turns out that when we entered the game, I was playing Veigar. I asked my teammates if they saw me pick Wukong, and one of them, and my friend said that I did pick Wukong. The other two said that they saw me pick Veigar.

Has this ever happened to anyone else? And what would be the cause for a bug like this?