The Downer - S3-E37
Continuity mistake: Gumball is being overtaken by the darkness, and there is a coffee table in front of him. When he escapes the darkness in a few shots, the coffee table is missing.
Continuity mistake: Toll booth men are throwing fines and tickets at Richard's car. These tickets and fines disappear in a few shots without being blown away by the wind.
Continuity mistake: When Richard is driving down a highway, he makes it into a lane with a truck in it. In two shots, the truck has vanished.
Continuity mistake: Gumball is talking to his dad in front of the couch. In two shots, Gumball is now at the door.