Factual error: At the dance in 1947, a US flag with 50 stars is visible.
Continuity mistake: At the beginning of the scene where Dr. Grant gives Jack the crank for the satellite dish, Henry turns his hat around so it is backwards, later on in the scene it is now facing forward, then is backward again, then at the end of the scene he is seen facing it forward.
A New World - S4-E2
Continuity mistake: At the end of the previous episode, when Jack comes home to find Tess there, Tess says "I thought you'd never get here" and then asks if he wants a drink and goes to the kitchen. In the beginning of this episode (which is suppose to be the same scene) she says "I thought you'd never get home" and Jack replies "you're not in Australia" and then Tess asks S.A.R.A.H. to make him lunch.
All the Rage - S4-E3
Continuity mistake: When Fargo and Jo are going to the section three lab, a scientist holding a beaker runs into them. He spills the liquid and bends down to clean it up. The amount on the floor changes from shot to shot.
All the Rage - S4-E3
Revealing mistake: In the very first shot, we see the sky, and you can tell it's a digital image imposed on a green screen instead of a shot of the actual sky.
Continuity mistake: When Jo is waking up from her surgery, both hands are on her stomach. The shot changes, her right hand is on her chest and her left hand is off her stomach.
Continuity mistake: At the end of the previous episode, when Carter tells Grant not to plan the wedding just yet, Carter leaves Cafe Diem and Grant says "May the best man win," as an aside. In this episode, the replay shows Grant saying this while Carter is still in the cafe, just in front of him.
Revealing mistake: When Jo comes riding in with the horses, you can tell that it's a stuntwoman in the far shot.
Continuity mistake: When Jo comes up to see her new house burned down, there's a lot of sunlight. When Zane passes by, the shot changes and nearly all the light is gone, as if it were dusk.
Continuity mistake: In the scene with Dr Lee, the old man, at one point, he waves with his left hand, then the angle changes and he's waving with his right hand. (00:20:35)
This One Time at Space Camp... - S4-E18
Plot hole: When Dr. Hughes is racing to save Allison when he thinks he is Carter from the events that happened in "I'll Be Seeing You" Henry says he is racing for a cliff, and that the cabin was just a hologram. But in the episode the Cliff was the hologram disguising the cabin. Henry even commented in that episode that he did not remember a cliff being there.
This One Time at Space Camp... - S4-E18
Other mistake: When Holly and Fargo are playing Dungeons and Dragons, Holly rolls a d20 die and yells, "Critical hit!" but we can see the 20 on one of the upper sides of the die, meaning that she actually rolled a 2, which is most definitely not a critical hit (and actually nearly a critical miss).
Continuity mistake: When Andy pushes Jack out of the way when the F.T.L. is malfunctioning he is pushed into 2 stacks of crates, they are seen all falling away from him. The next shot of him he is just falling against the crates and one of them falls on him instead of away from him and the other stack stays where it is.
Continuity mistake: Issac slips and falls on Jack's melted jeep - the shot changes and we see him fall again.
Continuity mistake: Before the launch when the countdown timer speeds up, the timer shows 21:09 and counts down to 21:00 then goes up to 21:59 instead of 20:59. Later the timer is at 18:08 and in the next shot of the timer it's at 18:18.
Continuity mistake: When Henry stops the countdown to launch, the time stops at 5 hours 13 minutes and 32 seconds. Later after the events at Cafe Diem the clock is stopped at 5 hours 13 minutes and 11 seconds.