Other mistake: The Time Expansion Helmet was supposed to allow Dexter to perform his 30 minute morning task in 30 seconds. Since this is the case shouldn't the cat have hit the fishbowl ages ago as time is not frozen.
Other mistake: In the closed-captioning, when Arnold and Gerald "touch thumbs" (and you hear that "sproing" sound), the caption says "[glass shatters]"
Monkey Fun - S2-E13
Other mistake: Season 2 episode 13 "Monkey Fun": Just before the enlarged Titano appears at the zoo, there is a family watching normal-sized monkeys in a cage. The family father (farthest on the right) has a drawing disorder with his eyes: their pupils look up and down, respectively, giving him a rather goofy expression.
Blue Wants to Play a Game - S1-E12
Other mistake: The jigsaw puzzle Steve and Blue help Shovel and Pail with has a picture of everyone playing musical chairs from the Mailbox's Birthday episode, but Steve suddenly isn't in the puzzle. He played musical chairs, so he should've been in the puzzle.
Other mistake: When the Hulk takes down the S.H.I.E.L.D. helicopter, it is shown crashing to the ground with its pilot parachuting to the ground shortly after. However, the pilot was never seen ejecting and the helicopter's cockpit door was still closed when it crashed to the ground.
Midori no chikyû wa makasetoke - S1-E2
Other mistake: When Yurika restarts the Nadesico, one of the screens pop up with a huge congratulatory "SAFATY ROCK OFF." (00:18:05)