Revealing mistake: If you look carefully when Neelix shoots the bins of water causing the water to rush out you can see a faucet opening on one of the bins.
Revealing mistake: Right at 40:30, if you look in the top left corner of the LCD screen, you can see a mouse cursor. Six seconds later it starts to move around. It seems like someone noticed and tried to move it out of the scene. (00:40:30)
Revealing mistake: When Tom is reading the Klingon romance novel, he presses the button to turn the page, yet the text is always the same.
Revealing mistake: When Paris and Rayne are driving through the Los Angeles suburbs in her van, they never change their direction of travel, but they pass the same sequence of houses twice. (00:31:05)
Revealing mistake: When Kes is eating the spawn beetles, the same shot is used twice for when she scoops out beetles from the tray. The untouched beetles are all in the same place, and there is a beetle that is nearly flipped by her thumb both times.
Revealing mistake: When Seven hits Harry and sends him sprawling through the door, the guard starts to fall before Harry runs into him.
Revealing mistake: Tuvok is behind a forcefield in Sick Bay, with the Doctor, Kes, and Captain Janeway looking at him. He tries to break the forcefield and is rendered unconscious and thrown to the floor. Janeway and the Doctor rush to pick him up and put him on the bed. Before they start to pick him up, he lifts his head and starts sitting up (to assist them, not because his character is conscious). (00:38:26)
Revealing mistake: As Icheb's parents turn their faces towards the sun to look at Icheb, the edges of the prosthetics used for the ridges on their noses are visible.
Revealing mistake: As Seven starts to explore, there's a flashlight floating next to her. There's no atmosphere, therefore no breeze, but it's slightly moving before she touches it.
Revealing mistake: As the camera looks into the Jeffries tube, it's easy to tell that the view beyond the second bulkhead is a matte painting used to extend the set.
Revealing mistake: The line on the make up on the isomorph is easily distinguishable.
Revealing mistake: In the basement, when the camera is in a close up on B'elana's face, the edge of the prosthetic at the left side of her hairline is visible.
Parturition - S2-E7
Revealing mistake: On the bridge, as Tuvok monitors and reports on the pursuing ship's weapons, you can see what looks like a wristwatch on his right wrist as he works the controls. (00:35:35)
Revealing mistake: If you look closely at the hot air balloon, in the shot before the message is attached to it, you can just see a wire holding it up.
Chosen answer: Before Q sent the Enterprise to the beta quadrant to officially contact the Borg, there were already indications that the Borg was beginning to reach Federation territory. There were remarks towards the end of the first season of the Next Generation that several of the furthest Federation outposts were being attacked by some unknown enemy. They suspected the Romulans, but when contact with the Romulans was re-established, they learned that it was not them. The Hansens had simply figured things out much earlier than anyone else in the Federation. They learned about the Borg nine years earlier, but Starfleet mainly took notice when their outposts started getting wiped out. It is logical to assume that there were indications of Borg scouting parties and research efforts well before that.
Garlonuss ★