There But For the Grace of God - S1-E20
Continuity mistake: When the Goa'uld attack the alternate Earth they dial in so no-one can escape. However in future episodes the Russian Stargate program said that as long as a DHD was hooked up to their gate it would have priority. When the invasion happened they had a gate on the ship hooked to a DHD.
Suggested correction: The Goa'uld are well aware of this. All they would need to do is block the event horizon of their Stargate or disconnect the DHD and any incoming wormhole would default to the gate on Earth instead.
Revealing mistake: When the three are seen running to Apophis' ship (after taking out the Jaffas), the branches of the trees are shown to move because of the great speed they ran at. However, none of the leaves on the ground move.
Revealing mistake: You can tell the rocks of the cavern are CGI and they're walking in front of a green screen. For example, when everyone goes back to the cavern, with Nick, in one shot the rocks cover part of Teal'c's head.
Revealing mistake: As Col. Mitchell is chasing the sedan on the motorcycle, he takes a highway exit marked "Ladner/Surrey" which are suburbs of Vancouver, BC. The show is set in Colorado Springs, and confirmed as the episode's location from the police bulletin. (00:29:10)
Continuity mistake: When Col. Mitchell is talking to Col. Carter in the control room, the initial shot shows Carter appearing on a white computer display. The scene then cuts to a close up of the conversation and the display is black. It is also much thinner than the white display. (00:11:45)
Visible crew/equipment: While the Wolf/Dakaya is on his way to the stargate, you can see a hand on the left side, maybe calling/showing him to the right direction. (00:32:40)
Visible crew/equipment: Near the end of the episode, when the team, Baal and Adria are solving the puzzles in the cave. As the camera is focused on Sam and Mitchell, just to the left of the screen the camera crew can be seen, with sports trainers visible and camera equipment.
Factual error: In the scene where O'Neill and Maybourne are looking up NID flight plans, the plan viewed on the computer lists the destination airport as Minot Airport Base, but provides the airport code for McCarran International Airport (KLAS). It also lists non-existent runways, as in runway headings that do not exist anywhere in the world. (00:24:15)
Other mistake: In the last few minutes of this episode, Carter uses the DHD to dial home. She enters the first chevron, then the "Cannon" dies. And when she proceeds with the dialing,the first chevron is still encoded, and you can hear that she enters seven additional chevrons, which gives an equal of eight chevrons, and then engages the stargate. That would mean they are in another galaxy, referring to S02E15. In that episode they tried to dial the eight-chevron address from SGC but the computer wouldn't accept it. So, it is impossible that they would be in another galaxy.
Stronghold - S9-E14
Revealing mistake: Just after Sam shouts to Mitchell to wait for back up, there is a side shot of a soldier firing a machine gun. There are cases going into the gun without the actual bullet in them, showing they are blanks.
Other mistake: When Dr. Carter is dialing the Asgard, the chevrons spin and lock in, but the screen only shows 7 chevrons locked in. The Asgard required 8 chevrons to reach them.
Other mistake: When the Asgard arrive to save the day they start by beaming out the Goa'ould but Teal'c gets left behind. He should have been beamed out with the rest of them.
Suggested correction: The Asgard know about Teal'c from the season 2 episode "Thor's Chariot". In that episode they upload his DNA profile into the Asgard computers so that he is not beamed away with the other Jaffa in that episode. His profile would have been kept so that he would known in any future contact situations with the Asgard.
This correction seems to have been made without watching the episode (or remembering the episode). The Asgard spoken of are from an alternate reality when they never met Teal'c (and don't have his DNA). One could suggest that alternate reality Carter told them about Teal'c, but there were two of them, and she wouldn't have known alternate reality Teal'c was later killed.
Children of the Gods (1) - S1-E1
Plot hole: When Apophis and his Jaffas are leaving SGC with the captive soldiers - there is no way they could have activated the gate without a DHD, but somehow it gets activated, and they escape.
Other mistake: When first discussing the alien ship, the computer screen states "terraforming progress" long before they suspect and later discover the ship to be terraforming the planet. (00:00:04)
Plot hole: The team go through the gate to disable a drone with the intention of being able to close the active Stargate, but once they go through in a submarine, the gate closes behind them, rendering the mission pointless. (00:24:18)
Suggested correction: This entry seems to have been made without watching the episode or you skipped a part. When the 3 enter the Stargate via the submarine, the Gate does NOT close behind them. It stays open, which we not only see but is how they can communicate with O'Neill. Then Dr. Markov says once they bring the drone in (to the submarine), they can shut the drone off and the Gate will close. Which is what they do (off-screen) and when they do, the Gate closes.
Other mistake: Just after the scientists on an alien moon follow The Light into the forest there is a car behind them.
Plot hole: Despite the Russian Government not being aware that the submarine is quarantined in a US port, a Russian Navy Sovremenny-class destroyer is visible in the background. (00:14:29)
Other mistake: When Jonas says he has flashes of what's going to happen (and no-one believes him), Teal'c says they have encountered many strange phenomena but no-one who could see the future. Except Jack and Teal'c had a whole "Groundhog Day" episode where, because they were stuck in a loop, they could see the future. Carter then says it goes against all the laws of physics as we know them, despite knowing time travel and other things that break the laws of known physics exists.
Citizen Joe - S8-E15
Factual error: At the end of the episode General O'Neill is introduced to Joe's wife. He is introduced as General O'Neill, but his insignia on his dress blue uniform is a Colonel - an eagle, not a General's star.
Suggested correction: There is no eagle insignia on his uniform. He has one star (on each shoulder) to signify General.
