Audio problem: When Penny turns into a dragon, she begins to say something, but her speech goes faster than her mouth movements.
Audio problem: In "The Robot", Gumball whimpers while his mouth is open. He whimpers again, and this whimper sounds like the first one, except his mouth is closed.
Audio problem: When The Butterfly lands on one of the construction workers, he says "Get it off!", but his mouth doesn't match the movements.
The Microwave/The Meddler - S1-E17
Continuity mistake: In "The Meddler", Nicole is feeding Gumball food with a spoon and drops it on the table. The camera cuts to Darwin and then back, but the spoon is now gone.
Nicole Watterson: Well maybe it all comes back to the stupid name you gave me!
Gumball Watterson: Um, what's wrong with Nicole?
Nicole Watterson: Nicole is my middle name, my first name is DOCTOR!
Trivia: The voice of Gumball in Japan is voiced by Junko Takeuchi, who is also the voice of Naruto Uzumaki.