I just played my first game, before that I updated avast. Champ select worked great, but trying to load into the game was impossible. I kept getting a bugsplat, until I remembered that the avast issue happened before, and because I updated avast, I wondered what would happen if I disabled avast. So I disabled avast for 10 minutes (back then it would be okay.) Game started and everything was fine, until these 10 minutes were up. My in game screen started flickering and not long after I got another bugsplat. I disabled avast fully until the game was over and since then I didn't get issues anymore, so I can say with 100% certainty that the new avast update brings issues with league once more.