Experiment - S5-E18
Revealing mistake: In the first scene, Lois is feeding Jamie while talking to Dewey. In the next clip, it changes to just a prop baby doll toy with a beanie covering a majority of his face. (00:04:25)
Revealing mistake: In an imagination sequence Reese and Malcolm are throwing around Jamie, but you can see it is a doll.
Continuity mistake: When Susan arrives Hal is holding Jaime, and the baby's entire body changes position between shots repeatedly - in some shots the front of Jaime's body faces Hal, yet in others Jaime's back faces Hal.
Continuity mistake: After Stevie becomes catatonic, a wrapper from a chocolate bar lands on his face, covering his glasses. The shot cuts and it's on his shoulder and then cuts again and it's on his face again.
Continuity mistake: When Malcolm is throwing the dodgeballs at Stevie, the number of balls in the bag changes between shots.
Character mistake: When Otto tells Francis he has to put a horse down, Francis objects saying he's never killed anything bigger than a poodle, and that was an accident. However, in season 4 (episode 11), Francis accidentally killed Otto's pet cow. (00:11:30)
Revealing mistake: When Lois confronts Susan about not telling her about Susan's kidney disease, Susan is telling Jamie how cute he looks in his sailor outfit. When the camera is moved to a different angle, it becomes very obvious that "Jamie" is just a prop baby doll. (00:11:10)
Audio problem: You can hear the new boss speak, but her mouth doesn't move. (00:16:30)
Answer: It is made up - although it is implied she is Croatian, she never mentions it herself.