Client Quits Out Within 10 Minutes of Every Game

It's about 8 minutes into the game. I'm top as Garen facing a Darius. I engage and then -- BOOM. The client quits out and brings me to the reconnect screen. An error message also occurs and I click "send report". By the time I reconnect I am dead.

This is only one of countless instances where this problem has occurred within the past 5 days. The kid I duo with can still hear and talk to me through the clients voice chat and I can communicate with him as well. It doesn't seem to matter what internet I am on either because it has happened on several different WiFis. The computer I use is a fully updated MacBook Pro that I got in 2015.

Does anyone know anything about this issue or has anyone experienced something similar. Please let me know because it is usually a guaranteed death for me in game because it seems to happen at the most inopportune times, and I don't want to continue playing knowing the client will inevitably quit on me and give me a BS death.