Continuity mistake: Season 5, Episode "Grave Danger" (parts 1 and 2); there are a number of shots of Nick in the grave which don't match what the CSI team see via webcam. For example when he is speaking into the tape recorder he is holding it above his head from the view inside the grave, but from webcam he is holding it further down.
Continuity mistake: During the scene where Catherine goes to her father for the money to save Nick, the character played by Frank Gorshin is talking. At one point he is seen from the front and puts his hand up to fiddle with his collar/neck. The shot changes to a side view and both of his hands are suddenly in his lap with no time for him to have put his hands down.