Continuity mistake: When Ryan is lighting Marissa's cigarette with his, at the start of the shot it's full, then the shot goes to Ryan and it's still full. But then the shot goes to Marissa and if you look at Ryan's cigarette you can see it is almost all gone. Then the shot goes to Ryan and the cigarette is full again. (00:09:00)
Sophia Lopez - S1-E4
Continuity mistake: When Matt talks to the "fluffer", her lollipop disappears from her mouth in between shots. She then raises her arm and puts the lollipop back in her mouth. (00:20:35)
In the Dark - S4-E22
Revealing mistake: When Tony is telling Gibbs & Ducky that Abby got a hit on the dead sailor's fingerprints, Gibbs takes the file from Tony; the camera shows the file, which appears to be a legitimate profile sheet, but in the comments section, is the script that Tony just read aloud. (00:07:36)
Visible crew/equipment: When Roger's holding the twins over the railing, Cindy grabs Maura, but Roger drops Vivian, and just as he lets the little girl fall we can see both hands of a crew member at the bottom of the screen.
Continuity mistake: When Rube's talking to the graffiti artist, he's painting what looks like a blue cat. We cut away, hear a brief paint spray, then cut back. There's now far more painted than that spray could have achieved, and what was there already has changed as well.
Songs to Love and Die By - S4-E10
Visible crew/equipment: When Keith is racing down the hall, Lucas follows and the ceiling of the high school set is visible. (00:19:05)