What the hell is this?

There's something wrong with the client that's been happening to me since patch 6.8. It usually happens when it's my first game of the day, but every time champ select finishes and the match is about to begin, the client freezes up and doesn't go to the loading screen until maybe 3-4 minutes after.

This puts me in the game at about 4 minutes in, leaving me behind. I lost two ranked games because of this.