Bungie has implemented a few changes to matchmaking and quitter penalties for the Control playlist, as detailed in This Week At Bungie post.

Players who quit out of Control matches can now trigger the Crucible suspension system–something players did take note of as soon as the update went live. For some, it was an unwelcome change since they considered the Control playlist to be the “casual” PvP mode, as opposed to more intensely competitive ones like Trials of Osiris and Survival.