Leaverbuster Bug

Earlier today, I tried to play a team builder match and was discontented during the loading screen. I fixed later, since it was a corrupted file issue, and returned to play the match which was already 10 minutes in. After the match finishes, I get a noticed that I was AFK and was being punished for it. On top of that, it was a 20 minute long wait for 5 matches. Is this normal? I returned to the match and played it until the end, so why am I getting punished for that? And why is it a 20 minute long wait?