Requiem for Methuselah - S3-E19
Visible crew/equipment: The monofilament line holding M-4 aloft is visible in the lab when the floating robot delivers the processed ryetalyn to McCoy. (00:17:20)
Continuity mistake: When Kirk splits up the landing party, he asks McCoy to further inspect the vegetation. In the two shot, McCoy isn't wearing his tricorder, but in close-up, it's there, strapped over his left shoulder. Cut back to the two shot, though, and it's gone again. (00:10:20)
Revealing mistake: During the battle scene, the use of special effects stock footage of the view screen, as seen over the helm from the opposite side of the bridge, briefly turns the short, brunette Ensign Chekov into a tall, thin blond guy. (00:44:20)
Factual error: Spock says the Klingon ship is approaching at Warp Six, but Sulu counts off the distance at about 50,000 kilometers per second - that isn't even the speed of light.
Continuity mistake: In the beginning Chekov disappears off the bridge for a moment and is replaced by a blond haired crew member, then he returns.
Let That Be Your Last Battlefield - S3-E15
Revealing mistake: When Lokai leaves the bridge near the end of the episode, when he goes into the turbolift on the bridge he heads right as soon as he enters, giving away the fact that this is not a small enclosed area. (00:45:45)
Other mistake: After Chekov goes beserk on the bridge and Dr McCoy and Scotty restrain him, Spock enters the scene and grabs Chekov by the sides of his face. His hands are close together as a human's face is around eight inches wide. When the camera cuts to Chekov's perspective view of Spock, Spock's arms are spread way far apart. Either Chekov's face has ballooned to over two feet wide or Spock is grasping the Panavision camera by its two sides. (00:14:34)
Is There in Truth No Beauty? - S3-E5
Deliberate mistake: While Miranda is with Kollos, McCoy tells Kirk that he didn't reveal her secret because he respects her privacy, then when Miranda steps out of the room and concedes to obey, the next closeup of Kirk is a flipped shot. (00:34:05)
Continuity mistake: As Mira is speaking with the alien's voice, Spock is behind a console that has a piece of equipment attached to it. From behind Spock, the piece is to his left, but the close ups of Spock show him close to and directly in front of it.
Requiem for Methuselah - S3-E19
Other mistake: As the miniaturized Enterprise appears on the table, the support for the model appears as well.
Is There in Truth No Beauty? - S3-E5
Plot hole: When the Medusan Ambassador Kollos and Dr. Jones materialize, the latter is wearing a protective visor and Mr. Spock can see that. Spock then mistakenly addresses Dr. Jones as Ambassador Kollos. Spock's suddenly illogical mistake seems odd: why should the Ambassador need to wear a visor? Shortly after, why do both Jones and Spock wear visors while carrying the Ambassador's still closed gasket to his cabin? (00:01:45)
Continuity mistake: On the bridge, watch Uhura. She goes from both hands on her controls, to left hand on her earpiece in a split second.
The Enterprise Incident - S3-E2
Other mistake: When Chapel comes into Sickbay and looks at the "dead" Captain, the camera goes to close up of Kirk, and he wakes up. After she yells for McCoy, the camera goes back to Kirk, and he goes back to sleep. The motions of him waking are obviously played in a slow reverse instead of him quickly closing his eyes.
Continuity mistake: Lt. Galloway, who was killed off the season before in "The Omega Glory," is resurrected without explanation for this final episode. (00:24:25)
Continuity mistake: When Elaan visits engineering, the close-up shots of Scotty show a security guard wearing a black utility belt standing in the background. But the man is missing in all the full shots. (00:13:15)
Revealing mistake: When Kirk & Spock beam down with Lincoln to the supposedly newly-created non-volcanic landscape, there are footprints all over the ground. They disappear a few shots later, though.
Revealing mistake: When Kirk pushes Plasus against a rock wall in the mine, a huge upper section of the "solid rock" wobbles. (00:43:20)
Requiem for Methuselah - S3-E19
Revealing mistake: When Spock examines the unknown Brahms waltz, we get a close-up of the music. Unfortunately, the hand-written score bears no resemblance whatsoever to the piece Spock has just played, though he expressly identifies it as such. (00:19:10)
Continuity mistake: When Mr. Scott asks Watkins to check the bypass valve, Watkins is facing the engineering boards with both hands on the panel. When we cut to a different angle, however, he's suddenly jumped to a position facing Scott with only one hand on the panel. (00:18:35)
The Empath - S3-E12
Continuity mistake: The bruises on McCoy's face change configuration, color and texture between the time Kirk and Spock first find him and the scene where Gem heals him. (00:34:15 - 00:40:30)
Answer: After causing Norman to overload, all of the other androids shut down. The same could be said for the androids on the Enterprise.