So Near, Yet So Farfetch'd - S1-E47
Continuity mistake: When Team Rocket takes off in the boat, it sinks. Their pokeballs float away, and Jessie says "Arbok and Lickitung are floating away!" But she doesn't catch Lickitung until Princess Versus Princess (Season 1, Episode 52).
Suggested correction: It's because these episodes were aired out of order.
That's true because of Electric Soldier Porygon.
Continuity mistake: Takumi and Shingo both have their right hands duct taped to the steering wheel, as per the rules of the Gum Tape Deathmatch. During one shot of the race, Tak's hand is no longer taped and resting casually on top of the steering wheel as opposed to the right side of it.
The Powerpuff Girls Best Rainy Day Adventure Ever / Just Desserts - S2-E10
Continuity mistake: When Marrianne calls Harold to the table, the plant in the middle disappears as they climb on top of it.
Winning Through Intimidation - S1-E15
Continuity mistake: Panik's Metal Guardian can be seen on the field several minutes before he actually plays it. (00:10:30 - 00:13:00)
Learning Curve: Part 1 - S1-E5
Continuity mistake: When the ship has made it through the plasma jump and is approaching the Universal Library, the images of the Watchers the ship passes by go from being transparent, to solid, and then back to transparent.
Continuity mistake: In the episode "Fool's Gold" Debbie puts the fool's gold on top of the pail on her sculpture. The shot changes and it's gone, the next shot it's back.