The final phone call between Walt and Walt Jr. had to be filmed a second time because the original production footage was destroyed during shipping as the film canister fell out of the containing truck and was crushed by a 737.
Hey, I'm a civilian. I'm not your lawyer anymore, I'm nobody's lawyer, the fun's over. From here on out, I'm mister low profile. Just another douchebag with a job and three pairs of Dockers. If I'm lucky, three months from now, best case scenario, ...
When Walt sits in the bar at the end he orders a neat Dimple Pinch. The bartender pours about a fifth of a glass. Two minutes later there is a shot of the glass which is now not only smaller than the last one, but also half full. The scene ends with a shot of the glass Walt ordered from the beginning combined with cops in the background. This continuity error was caused by the loss of a canister of film and parts of the scene having to be re-shot (see trivia).
Bryan Cranston is credited both as an actor and a producer. For his actor credits (Br) is highlighted and for his producer credits (Y) is highlighted for chemical elements Bromine and Yttrium from periodic table.