When the Dead Come Knocking - S3-E7
Audio problem: When Rick and his 'strike force' hole up in the cabin surrounded by walkers. They arouse the cabin's owner who brandishes a double-barrel, breech breaking shotgun. When characters brandish pump action shotguns, often they pump a round for effect and the sound effect is characteristic. The pump action sound effect is erroneously applied to the breech breaking double barrel shotgun.
Audio problem: In the scene when Andrea is mourning the death of her sister, Rick walks up to "tell her how it is." Andrea points a gun at Rick with just her right hand. When the gun is coming up to Rick we hear the slide being cocked, this can only be done with two hands. (00:03:35)
Chokepoint - S9-E13
Audio problem: Lydia is hammering a nail in a board trying to barricade a door. The sound of the hammer hitting the nail is slightly off.
Answer: The walkers could have knocked them down more than once. There may have been another wave that knocked down the fence earlier and they're going to put it up again soon.
Captain Defenestrator