Visible crew/equipment: When Kim is talking to Joan the security guard, a crew member drinking a cup of coffee can be seen in the dojo.
Gabby's Gold - S3-E8
Revealing mistake: When Kim and Gabby swing from the bar to kick the two villains, its obvious that Gabby kicked the guy in the knees, but he falls holding his chest. Plus Kim was a good 8-12 inches from her target and he fell anyway.
Continuity mistake: The rebels are in their stocking feet when they narrowly escape the Zompyres at the lab, but they are wearing shoes when they get back to the base.
Suggested correction: They had removed their shoes prior to entering the lab, remember the scientist said 'thank you' to them for it plus the Zompyers were distracted by the dancing so the rebels could have grabbed their shoes before exiting the building.
Factual error: Jack enters the tournament as a recognized white belt but he is scheduled to face Kim who is ranked as a black belt. Tournaments do not allow match ups between white and black belts; it's forbidden in all styles of martial arts.
Factual error: It says that Jerry is running a judo dojo, but when Jack walks in Jerry is teaching his students to punch - judo doesn't use punches.
Revealing mistake: Kim is supposed to be hanging from the tree by the ropes around her wrists, but you can see she is standing on a platform.
Gold Diggers - S4-E2
Visible crew/equipment: At the end of the episode when Milton is talking to Jack, a tube is seen next to his legs for the dust to come out. (00:36:00)
Continuity mistake: When Milton pushes the vole down the ramp and hits the wall it falls off the board. In the next shot it's back on the board.
Continuity mistake: The ninja with the tattoo that attacks Jack is a large built man with olive skin. When Jack sees the tattoo on Kai's teammate, he is now a slight built, Caucasian teenager.
Continuity mistake: The kids fall to the ground after they are eliminated from the game but when Jerry takes out a knight and the wizard along the path, only the knight is seen lying down in the subsequent shots; the wizard is nowhere to be seen.
Continuity mistake: When Jack is talking to Kim after he defeats the impostor, in one shot you can see the actor who played the impostor appear over Jack's shoulder; he's just standing there watching the rest of the scene.
Visible crew/equipment: During the race, cameras can be seen on Kim's helmet.
Kickin' It on Our Own - S2-E21
Revealing mistake: At the karate demo, the Black Dragon student never breaks the second board, the kid holding it drops it as the kick comes close.
Continuity mistake: The Bobby Wasabi dojo receives the amazing Punch Master Elite that is apparently not even available in stores yet, however you can see the piece of equipment in a previous episode, S2E15: A Slip Down Memory Lane. The Punch Master Elite can be spotted in the back left corner of the dojo in the first scene. Other than that you can just barely see it if you look closely into the dojo when the camera goes to that angle in the scene where Jack regains his memory and breaks the under 15 record for brick breaking. Aside from these 2 sightings, you don't see it again because it is a flashback episode, and beyond that, you actually don't see it again until S2E20 when Milton opens it as a gift from the Mayor, awarded for tremendous bravery in capturing an escaped convict.
Continuity mistake: The lockers in the Bobby Wasabi dojo change from blue to green in the same episode.
Continuity mistake: In every episode Joan Malone's police name tag says a different last name.