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.
The Importance of Being Phoebe - S5-E11
Continuity mistake: When Phoebe is lying on the ground and is supposed to be unconscious, when Cole goes to pick her up you can see Phoebe throw her arms around his neck. (00:29:15)
Continuity mistake: When the girls first came out of the machine, they were actually just the size of insects, and the professor didn't need a helmet to see them, but when they was during the battle, he had to.
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)