Chief O'Brien's hairstyle reverts back to his "normal" 24th Century hairstyle once He and Dr. Bashir beam over to the K7 space station from the Enterprise. Moments earlier, his hairstyle reflected the hairstyle (combover with part) as worn by the 23rd century human male crew members.
When the bomb in the tribble in the grain storage compartment is first mention, the camera pans over the area and focuses in on one, solid brown tribble. When Sisko finds the hidden bomb-tribble later, it is brown with white.
The barroom brawl shots are presented in a different order than in the original episode The Trouble with Tribbles (1967). Watch Paul Baxley, the actor who plays Lieutenant Freeman and is at the table with Scotty and Chekov. About halfway through the fight, he is seen being tossed over the bar and out of the fight, but in a subsequent shot, he is seen on his feet, throwing a Klingon over a table and another one over his shoulder. The order of the two shots was correct in the original episode.
When Odo and Worf are in the bar on D7, a Starfleet Officer in a command gold shirt and Commander's sleeve stripes walks by in the background. On Star Trek (1966), Mr. Spock is the only full Commander ever seen on the Enterprise. Scotty was third in command and he was only a Lt. Commander. This means that either another starship was there (which there was not), or there was an extra Commander on the Enterprise (which there would not be).
Just before the bar room brawl, Bashir picks up a chair from another table. His hands changed position on the chair between shots.
When O'Brien incorrectly identifies the officer in the bar with Scott and Chekov as Kirk, Bashir asks why a captain is wearing lieutenant's insignia. However, in the original "The Trouble with Tribbles" credits, the character is credited as an ensign.
Incorrectly regarded as a goof: Since Bashir has previously revealed a lack of familiarity with uniform standards of the earlier era, this might well be intentional.
Incorrectly regarded as a goof: Since Bashir has previously revealed a lack of familiarity with uniform standards of the earlier era, this might well be intentional.
Years earlier Worf encountered an aging Scotty in TNG: "Relics". Prior to the mess hall fight on K7, Worf is once again in the same room with a younger Scotty, yet makes no mention of his previous encounter with the older one.
Incorrectly regarded as a goof: This could be an oversight, as Worf encountered Scotty later on in the engineer's life and possibly didn't recognize his younger self.
Incorrectly regarded as a goof: This could be an oversight, as Worf encountered Scotty later on in the engineer's life and possibly didn't recognize his younger self.
When the Defiant crew is trying to estimate the number of tribbles aboard K7 and the Enterprise, Dax states there are, "One million, seven hundred and seventy one thousand, five hundred and sixty one. That's starting with one tribble with an average litter of ten every twelve hours." Spock later makes the exact same estimate, showing that Dax and Spock are of similar minds, being the science officer of their respective crews. However, this fails to account for the time difference between when the two estimates were made. The rapidly-breeding tribbles would have been able to multiply even further from when Dax made her calculations to when Spock made his.
When Sisko and Dax are in the turbo lift, Sisko halts it by letting go of the control handle. After Sisko speaks with Kira on the Defiant, the turbo lift resumes movement without Sisko touching the handle.
During the bar fight, when a Starfleet officer in a yellow shirt gets thrown over the bar, it moves.
When Sisko climbs out of the grain storage compartment, part of the sole of his boot can be seen flapping loose.
Sisko and Dax work on a wall panel behind Kirk and Spock. In the original series footage, that wall is blank. There is no equipment panel there.
As Lt. Watley exits the turbo lift, after flirting with Bashir, a crew person's hand can be seen prompting an extra to start walking. The crew person then realizes the extra was going too soon and stops him briefly, then pushes him forward again. This happens very quickly.
Sisko and Dax plan to follow Kirk to protect him from Darvin's bomb, however, they somehow arrive in the commissary, and are seated playing a game, before he enters.
The elder Darvin is somehow aware that the Orb onboard the Defiant is the Orb of Time despite it being expressly stated that the Cardassian government, which had just handed it over to Starfleet, had never been able to determine its unique purpose.
Several characters make reference to the belief that the actions of the Defiant crew onboard the Enterprise and K7 station do not constitute a predestination paradox. However, the tribbles that Dax and Sisko threw out of the grain storage compartment (which repeatedly strike Kirk in the head) were present in the original series footage from which this installment is drawn, meaning that Sisko and Dax must have always been in that compartment throwing tribbles. This is inconsistent with the rest of the story, wherein characters and objects inserted into scenes create visible differences in events.
In the turbolift, Bashir says to O'Brien "Didn't you take basic temporal mechanics at the academy?" O'Brien is a non-com and never went to the academy.
When Sisko first tells the Temporal Investigations agents that the Defiant had been thrown back in time and encountered the U.S.S. Enterprise, they ask him to specify which Enterprise. When Sisko tells them it was the original Constitution-class Enterprise, the agents automatically assume that Captain Kirk was in command without yet knowing to when exactly the Defiant traveled back. The original Enterprise had five different Captains over her tenure of service. Robert April led the Enterprise's first five-year mission, Christopher Pike the second and third five-year missions, and James T. Kirk the fourth. William Decker then commanded the Enterprise during her 18 month refit, then Kirk again led the fifth (and final) five-year mission. Finally, Spock commanded the Enterprise after it was removed from normal service, for her eight-year stint as a training ship for cadets.
O'Brien, Bashir, Odo, and Worf decide against buying "Kirk" a drink because they don't want to run the risk of even the smallest alteration to the timeline, yet moments later all four readily participate in a bar brawl, which could have far greater consequences to history than buying someone who is already in a bar a drink.
The Defiant crew beams over to the Enterprise and K7 station to conduct a manual search for the elder Darvin. Ship's sensor scans have always been capable of distinguishing the life signs of different species, and Darvin would have been the only Klingon aboard either ship/station until the Klingon ship arrives later. Even if he was surgically altered to appear human, he still has Klingon DNA.