Continuity mistake: Miguel kicks and breaks a staircase railing during the school brawl. For a second it cuts to Robby. When it cuts back to Miguel, the railing is fixed.
Picture Day - S1-E6
Continuity mistake: I'm not sure what type of mistake this counts as, but in here it is. In the episode "Speaking of Cancer" in season four, Jennifer reveals that she has been lying to Jack and Katie about them all having a shellfish allergy for years because it costs too much for them all to eat it, but in the season one episode "Picture Day" Dave puts down a plate and Jennifer says "Ooh are those crab-cakes?" and takes one to eat. Jack was sitting next to her, so he should have heard this and tried to stop her.
Revelations - S3-E6
Continuity mistake: When Tim puts Lucy in the squad car after "arresting" her, the rear door on the driver side is open, but when the camera pans back to her it's suddenly closed without making a sound.
Cricket's Place/Volunteer Tilly - S1-E30
Continuity mistake: When Bill opens the bathroom door, it's brown, then green.
Continuity mistake: Just before the portal opens where Sonic comes out by a water fall, you get a good view of the ground around where he comes out at and there are no holes. But once he emerges, he looks around and then looks down and suddenly there are large holes that become what he focuses on. (00:00:25)
Continuity mistake: As Mark sits down next to Dan and reaches towards his backpack, in the very next shot he's pulling out a history book, even though he has not gotten anything out of the bag.
Continuity mistake: At the diner when Tsunoda and Retsuko are talking, Tsunoda pulls out a red phone with a white heart on it from her purse. In the close up she is pulling it out with her left hand and the phone is horizontal with the heart on its side. It then cuts to a wide angle and suddenly she's holding the phone upright with both hands.