Duck/Aren't You Chupacabra to See Me? - S4-E9
Continuity mistake: Mandy is in the library working on her report. When she's working on the second page, the writing is scribble, and on top of a stack of paper. A second later, the page says "CORN by Mandy", and the stack of paper is gone.
Episode XXIX - Couple on a Train - S3-E3
Continuity mistake: When Josephine grabs Ezekiel by his poncho, she is wearing a black glove on her right arm, but when the scene cuts to Ezekiel when he says, "What business is it of yours?", the glove disappears, showing Josephine's arm bare, but in the next shot, she is wearing both gloves again. (00:08:40)