The Hit Car - S1-E3
Deliberate mistake: When Starlet asks Ralph if he believes that stars can predict his future, Bill tells them to put a dimmer on the googoo eyes because of the killers on their tails, and the two shots facing Bill are flipped. (00:14:40)
Deliberate mistake: As usual when the Hulk reverts back into Bruce Banner, he is left wearing nothing but tattered pants. When Mitch McCutcheon sneaks Bruce Banner into the nuclear research facility, Banner is shown wearing his usual outfit of a gray collared shirt tucked into purple slacks that are intact. Given that the Hulk was just in the middle of the Nevada desert, Bruce Banner would be in no position to have a change of clothes on him, and the idea that the top secret facility would have an exact match of his go-to outfit is ludicrous.
Winning Through Intimidation - S1-E15
Deliberate mistake: In the actual card game, attacking the castle ring would not be allowed, but this is probably done in order to enhance the show for kids.
Episode XCII - S5-E1
Deliberate mistake: Jack stops his motorbike beside a stream, and Jack's weapon strap crosses over his left shoulder when he walks over to have a drink. The problem is when we see Jack's reflection in the water, his image is not reversed; note the strap is still crossing over Jack's left shoulder. (00:07:20)
Deliberate mistake: When the turtles and April escape the building filling up with water, the shot where the hall is filling up with water is used twice.
Deliberate mistake: Probably best for filming the scene, but Jennifer Hart pulls up and parks her car on the street on a red curb in front of an ambulance and walks away. (00:10:12)
The Defection of Hawkeye - S1-E8
Deliberate mistake: When Mandarin is watching and wondering why Julia is tailing Clint, the road surface and cliff walls around Julia's car are recycled repeatedly. (00:10:55)
Did You See the Sun Rise? - S3-E1
Deliberate mistake: When TC is flying the stolen Loach toward the Japanese delegation, there are multiple exterior flipped shots showing the stolen helicopter backwards. There are also flipped closeups of TC while flying, note position of his helmet mic, etc. (00:34:35)