Visible crew/equipment: When Jax and Clay are meeting with Alvarez (when they figure out the niners are branching out), the camera man is visible in Alvarez's sunglasses.
Continuity mistake: When Wayne pulls back the blanket to look at Piney's body, he doesn't cover it back up but when Wayne stands up, Piney is covered up again. Wayne is on camera the whole time so he couldn't have covered it back up.
Continuity mistake: The car shown in the scene when Jax and Tara are driving to Oregon is a Jeep Grand Cherokee. When at the gas station and in the park, the car has reverted to the Ford Edge that Tara is seen driving throughout the season. (00:06:25 - 00:15:30)
Continuity mistake: In the episode prior to this one, Clay severely beat Gemma in the face. Bruised and cuts. Swollen eyes. This episode, which is the next morning, her face isn't nearly as bruised - it sure wouldn't have healed that much overnight. And the swollen eyes aren't as bad either.
Revealing mistake: Piney, who has supposedly been dead for days, swallows and moves his mouth while Opie lies crying beside him. It is while Unser is telling him to go see Gemma's face.
Burnt and Purged Away - S4-E12
Continuity mistake: Near the start, Jax Teller's hat continuously turns around over the course of 30 seconds. (00:04:15)
Deliberate mistake: In the chase scene after Jax shoots the unnamed driver, the SUV crashes into traffic. You can see the car that the SUV hits is empty. (00:26:18)
Character mistake: The nurse that was helping the doctor tend to Clay has blood all over her gloves. As she leaves the room, she takes off one glove. No hospital anywhere would allow doctors or nurses to roam the hall with bloody gloves and hands. It's a health hazard.
Suggested correction: She leaves the room with both gloves on. Anyway, this can't be classed as a mistake because you don't see her at all after she goes through the door. She may have taken them off, off camera, as soon as she exited.
But a nurse wouldn't leave the room with them on, even if she took them off in the hall right away.
No doctor or nurse leaves the operating room with bloody gloves on! Come on.
Revealing mistake: In the scene where Jax and crew go to help escort Tig after he ran into Laroy with a car at the cafe, they get caught in a traffic jam and have to drive on the breakdown lane. Jax shoots at the SUV with Laroy and kills the driver and the car slams into a car that is stuck in traffic, but there is no one sitting behind the wheel of that car.
Other mistake: Look at the tombstones in the cemetery. I counted the name Carl Unger 4 times. Also the order of the tombstones changes several times. (00:14:30 - 00:16:10)
Suggested correction: You can never assume how someone would heal or swell.
Clay beat her severely. Perhaps you should watch the scene.