Star Trek: The Next Generation (1987)

The Big Goodbye - S1-E12

Other mistake: After greeting Crusher, Data explains where Picard is. Problem is he uses the contraction "he's" instead of "he is." Data is supposed to be incapable of this.

Encounter at Farpoint (1) - S1-E1

Other mistake: When Q the Judge enters on his throne, at one point, the hydraulic arm the throne is on is visible, despite being black to blend in. Conversely, in "All Good Things...", the final episode, the arm is missing having been matted out by CGI techniques.

Datalore - S1-E13

Other mistake: In this episode, when Riker makes his log entry, he says the stardate is "4124.5, " the 4-digit style of stardates from The Original Series, rather than the 5 digit style used in The Next Generation.

Too Short a Season - S1-E16

Other mistake: At the beginning of the episode, when Picard and Riker leave the bridge to head to the teleport deck to receive the admiral and his wife, as the lift door opens Patrick Stewart makes a face at the crew off-screen as he walks off the bridge. (00:02:05)

Haven - S1-E11

Other mistake: When Deanna's mother arrives on the Enterprise, the sound of the transporter activating is heard. But the transporter technician is seen behind Picard and Deanna, and he remains standing by the wall with his arms behind his back. (00:09:00)

The Big Goodbye - S1-E12

Other mistake: As Crusher enters the police station, Data says "Hiya, Doc. What's cookin?" He's supposed to be incapable of using contractions.

Lonely Among Us - S1-E7

Other mistake: As the Enterprise comes into the frame approaching the cloud, the registry numbers are reversed.

Where No One Has Gone Before - S1-E6

Other mistake: As the Enterprise comes out of warp in galaxy M33, the conference lounge is visible and is a re-use of the opening sequence. The movements of the people is identical.