missing death notifications

Playing an ARAM game as Malphite, with Jinx, Annie, Graves and Tahm Kench. Vs. Alistair, Ziggs, Ashe, Twisted Fate and Anivia.

I got 5 kills and 14 assists. I know for sure that my first two "You have slain an enemy" notifications did not show up, possibly others, and a few of the "An enemy has been slain" and "An ally has been slain" notices were missing too. I would say only about 1/2 to 2/3rds of the notifications showed up.

I was playing with a friend, using voice chat, and he said he was missing some of the notifications as well.