In Lobby with Friend, He was sent to game without me

I was in an ARAM lobby with a friend of mine. It sent him to a lobby, but I never even received notification of a game starting. I attached a screenshot where you can see us both in the same lobby, but he is in champ select.

Here's the match I missed, if it helps diagnose the problem: http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2411944882/37652930