Pick A Champ Bug?

Joined a normal match, enemy team picks first and I pick last. Just as the last enemy locks in their pick, the client bugs and a buffer circle appears on their champion. about ~5 later I get kicked from the pick and receive an alert that I left the game. When I didn't.... I had a stream going in the background the whole time, and that didn't lag or buffer. (So internet didn't drop). I was able to type in the game lobby, so I'm a bit confused on what really happened [sg-soraka] Why did I get a leaver buster for something I didn't technically do :(