Continuity mistake: Since Dax's spots were stencilled on individually every day, the shapes and patterns have a tendency to change slightly from scene to scene in any given episode.
Suggested correction: Unless you can cite a specific instance where the change is obvious (taking stills and minutely comparing the patterns doesn't count), this is much too vague to count as a mistake.
Emissary (2) - S1-E2
Revealing mistake: During the chaos on the Promenade as the Cardassians attack, a man can be seen landing on a steel girder that bends like rubber or foam when he makes contact.
A Man Alone - S1-E4
Other mistake: Aron Eisenberg's name is misspelled on-screen as Aron Eisenerg. (00:04:25)
A Man Alone - S1-E4
Other mistake: The word "Shifter" is written in English on Odo's office wall. Obviously, this is done for the benefit of the audience, but on a Bajoran space station near their home planet the word should have been written in their native language.
Visible crew/equipment: As Chief O'Brien closes the floor panel in the runabout, a mic pole and chord are visible on the left side of the screen behind Sisko. (00:10:35)
Revealing mistake: In episode 'The Passenger', when the Koblian officer opens Vantika's eyes to run a retinal scan, his pupils dilate, despite the fact that he is dead.
Deliberate mistake: The dying Vantika hides his consciousness away in a portion of Dr. Bashir's mind. At one point, "Bashir" (heavily cloaked in clothing and shadows) comes up behind Quark and makes sure his demands are clear. At this point, it should still be unclear just how Vantika is still "alive", and whose body he is using. However, when he shoves Quark away, for a fraction of a second, Bashir's face can be seen under his hood. They were true to plot in using the right actor (though he shouldn't have been seen), it is possible some might have spied the secret earlier than the show meant to reveal it.
Character mistake: In the scene where Lwaxana Troi follows Odo into the Turbo lift and it breaks down, Odo reports to Ops that they are in Turbo lift 7. Later scenes in Ops refer to their location as Turbo lift 4.
Continuity mistake: At the end of the episode, Odo has sent everyone affected by the telepathic matrix to a cargo bay. Sisko and O'Brien remove their com badges, throwing them aside before heading to the bay. After everyone is cured, Sisko straightens back up and, in the closeup, you can see that he has a badge on. In the next closeup, it's gone again.
Continuity mistake: When Kira is explaining to Jadzia in Quark's that she wants to get rid of Sisko, she is wearing her Bajoran earring in her right ear. When she picks Quark up by his collar a couple of shots later, the earring is gone.
Visible crew/equipment: When Jadzia and Melora are in the runabout talking about relationships, Jadzia mentions having to go back 150 years for a Starfleet relationship; when it cuts to Melora the boom mic can be seen coming in through the front window. (00:23:05)
Visible crew/equipment: After Kira returns the expensive gift to Zek, when Quark kneels in front of Zek we can see the T-mark on the floor, under the table. (00:23:15)
Factual error: The originally-aired version spelled the word "Acquisition" without the "c" and it appeared in the credits as "Aquisition." This goof has been corrected in the DVD versions.
Second Sight - S2-E9
Character mistake: When Nedelle collapses, everyone looks to Jadzia to save her and she says she can't. Why do they think Jadzia can save her? She isn't a doctor, and the Dax symbiant was never a doctor either. They are on board a Federation ship, with a Federation crew, why do they not call The Ship's doctor?
Plot hole: Just after the Kelleran soldiers kill all the scientists, O'Brien tries to contact the runabout Ganges for a beam out. Unable to contact the Ganges, he and Bashir use the T'Lani cruiser's transporter to beam down to T'Lani III. He could have used the cruiser's transporters to beam to the Ganges instead (it wouldn't have had its shields up as it was unoccupied and was closer to the cruiser than the planet) allowing them to escape back to the wormhole and DS9, instead of having to await rescue on the planet.
Other mistake: During the battle near the end of the episode, Sisko is heard saying, "Locking onto the lead ship" but he gives the firing order to Bashir, who is seated at the helm. This implies that the targeting controls and firing controls are at separate stations, which makes no sense.
Other mistake: When the Klingon, Kozak, falls on his knife during his fight with Quark his blood is a deep red. It should be pink like any other Klingon. (00:02:20)
Suggested correction: Klingon blood is only shown as pink in the film Star Trek VI: The Undiscovered Country and in the series Star Trek: Discovery. In the case of the former, the blood was shown as pink/lavender to have it appear alien and also to avoid rating issues (that much blood would have given the film an R rating). This is an inconsistency in the entire Star Trek universe at large, or perhaps only in those two stated instances, and not a mistake in this particular episode as the number of times Klingon blood has been red greatly outweighs the few times it has been shown as pink.
Continuity mistake: When Jadzia tells Benjamin she is going to do helioscismic measurements of the sun, the camera shifts in mid-sentence. In the first shot she is rubbing her hands in front of her, in the second shot, her hands are clasped behind her back. (00:15:20)
Plot hole: Thomas Riker is able to steal the Defiant partially because he's a genetic double for and not a clone of Will Riker. Thomas Riker's existence is not a secret. Star Fleet is aware that the first officer of their flagship has a genetic duplicate who resigned and is out there somewhere. There should be something in place to verify Will's location before giving Thomas access. But then, of course, we wouldn't have an episode.
Suggested correction: At this point Thomas Riker is still a Starfleet officer. There is no need to lock him out of accessing the Defiant's systems as he is considered just as trustworthy as Will.
It's said that he resigned over suspected Maquis sympathies. They were right.
They say that he had expressed political opinions that supported the Maquis, not that he had resigned from Starfleet. A large number of Starfleet officers supported the Maquis' intentions, but still stayed loyal to Starfleet.
No, Thomas Riker accessed the Defiant under the guise of being Will Riker, and Major Kira released the lockouts being under that impression.
Exactly. NOBODY in Star Fleet has thought "Well, what if one of them claims to be the other? How do we tell them apart?"
Plot hole: Earlier in the season, it was established that The Jem'Hadar are genetically engineered to be loyal to the Changelings, meaning they will not deliberately harm them. With that in mind, the Changelings still care about Odo's well being despite his refusal to return to them. So why didn't the Lovok Changeling send a message to The Jem'Hadar ships to inform them that a Changeling was going to be on the runabout? Given that he took time to offer another chance to return to his people, you would think he'd take time to make sure he returned to the station safely.
Suggested correction: Maybe The Jem'Hadar were trying to disable the runabout to try and capture Odo and Garak.