Continuity mistake: In the final scene the camera switches between shots from the front and from the back repeatedly. Parker's arms are folded when shot from the back, and by her sides from the front (and vice versa).
Continuity mistake: 4.03 - The 15 Minutes Job. Parker gives the target her number on the napkin, tells the guy to call her and takes a drink. The way she holds the glass changes immediately.
Continuity mistake: When Hardison and Spencer meet up with the rest of the crew, Hardison's suit is completely dry, despite having been thrown into a swimming pool in the previous scene. His collar is even pressed and starched. (00:16:50)
Continuity mistake: When Sophie is "shot", the two gunmen duck down immediately. When we see the flashback later, neither of them duck. One gunman walks away, while the other is revealed to be Elliot, who looks down over the barrier at the crowd for a beat before leaving.
The Snow Job - S1-E9
Continuity mistake: After the mark has seen the fake MRI, he's talking with Nate and Sophie in the hallway. Nate walks away to the back of the shot, but in an instant, he's right back behind the two of them, saying, "Whoa, Whoa."
Continuity mistake: At the beginning of the episode, the priest is mugged. As he's lying on the ground, his face looks fine, but in the hospital scene he has a huge gash on the right side of his forehead.