Continuity mistake: Episode 16, season 4, "The Day They Raided the Knights." In Max's apartment, Max sneaks up behind 99 to give her a kiss. She punches him in the jaw and he falls back against the wall to the right of the doorknob. The scene changes to a close up of Max and he is sitting on the floor to the left of the doorknob.
Continuity mistake: In episode 17 of season 4, "Tequila Mockingbird," Max is going to pour tequila in Valdez's glass. The camera closes up to show Max picking up a bottle with a candle on it. The candle falls into the glass. When the camera angle changes to show Valdez and Max, the candle is gone.