Beyond the Farthest Star - S1-E1
Other mistake: When showing Scotty on the bridge, some of the frames show more of his body than others. In those frames, you can see that he lacks legs.
Beyond the Farthest Star - S1-E1
Continuity mistake: There is an alien in a Starfleet gold shirt sitting next to Sulu. For a second, there is a human in a Starfleet red shirt, then it goes back to the gold shirt alien.
Continuity mistake: When Uhura's rescue party is in the transporter, Chapel's uniform is blue. When they materialize on the planet, it's red for a moment, then blue.