I cant prove it but
I'm pretty sure every time my client disconnects during load screen and I get leaver buster, it pairs me with teammates that are flagged as toxic.
I can see this because my client has crashed like 6 times in the past 2-3 weeks and every time it thinks I've afked (even though they were all remakes) I see the change in players on my team. Then after a 5-10 games it fades away and then it happens again the next time.
Of course I can't prove it and I know Riot would never admit to something like this but I'm pretty positive this is going on.
Anyone else have experiences like this?