I watched the season 4 ending and the story is that Huell underhandedly replaced Jesse's cigarettes with an other pack. Jesse desperately looks for the ricin cigarette at the hospital and thus empties out every cigarette.
At this point Walt has the ricin, Saul has the old cigarettes and Jesse think Gus poisoned Brock.
So in this last episode, Jesse is leaving Saul's office, Huell lifts his dope and somehow he ends up with his old pack of cigarettes that used to contain the ricin.
Did Huell put it back ? Why in the world would he do that ?