Amumu Ult Prevents Auto Attacks
Amumu's ultimate is a snare, and I thought that if you were snared, you could auto attack and use abilities for the duration of the snare, except for movement abilities. However, in a game of ranked, I experienced what I believe to be a bug. For the duration of Amumu's ultimate, I could not use auto attacks, even though Amumu himself was in range of my attacks. I was playing Miss Fortune when I experienced these problems.