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.
Character mistake: Brock states that the Diglett are plowing the ground and the Dugtrio are planting the trees, but the opposite is true (The Dugtrio are plowing, and the Diglett are planting).
The Ninja Poke-Showdown - S1-E32
Factual error: When Venonat uses Stun Spore, Ash tells Bulbasaur to use Whirlwind. Bulbasaur just blows the powder away with his mouth, but he doesn't use the Whirlwind attack. He can't learn Whirlwind in any of the games, and what Whirlwind is supposed to do is to blow the opposing Pokemon away. Ash could have just as easily told Bulbasaur to blow it away, but he instead chose to tell him to use a move that he can't possibly learn. The only Pokemon that can learn Whirlwind are either Flying types or Bug types; i.e., Pokemon with wings (with the exception of Makuhita and Hariyama, which weren't introduced until generation III, and did not exist at the time this episode aired). In The School of Hard Knocks (Season 1, Episode 9), a character mentions information regarding a Pokemon's levels, attacks, and information which is taken straight out of the game, so it's very clear that Bulbasaur should not be able to use Whirlwind. [This is a result of mistranslation. In the original, Japanese version Ash orders Bulbasaur to "blow it away." He didn't say Whirlwind. Still a mistake in the English version.]
Pokemon, I Choose You! - S1-E1
Continuity mistake: When the capsule containing the three Poké Balls first opens up, you can see the names of the Pokémon etched into the balls (in Japanese), but when Ash picks them up, the names are gone.
The March of the Exeggutor Squad - S1-E41
Other mistake: The Pokemon Exeggcute is shown evolving in to an Exeggutor naturally. But the Pokemon Exeggcute can only evolve into an Exeggutor with the use of a leaf stone. In the Japanese version, there is a mention that something in these woods causes Exeggcute to evolve without using the Leaf Stone (when Exeggcute evolves, James even mentions that there is no stone). However, as this was skipped in the English version, it creates a plot hole.
Character mistake: During the recap, the narrator says that Ninetales had defeated Squirtle by using Ember, but Blaine ordered it to use Fire Spin. [This error doesn't appear in the Japanese version.].
Other mistake: Assunta's Ivysaur attacks Sparky too early, before the battle even started, not to mention Assunta haven't given it any commands during the battle.
Factual error: When we see that Dodrio's neck is tangled, the configuration doesn't make sense. It just looks like two bands of neck, but it doesn't reflect what it would actually look like if it was really tangled.
Character mistake: When Mandi brings out Golbat, Brock says, "Kingler is really weak to air attacks." But Kingler's a Water type, which has no weakness to Flying-type attacks.
Suggested correction: Brock is saying that Kingler is vulnerable to attacks from the air, not that it is weak to Flying-type moves.
Mystery at the Lighthouse - S1-E13
Other mistake: When Professor Oak goes to rotate his monitor, his right index finger is intermittently not coloured in. (00:09:15)
The Battling Eevee Brothers - S1-E38
Continuity mistake: When Pikachu and Eevee are first talking, the beam closest to the screen is smaller than the others, but in the next shot, it is larger. Also, there is a tree to the left of Pikachu, but in the next shot, there is not. Additionally, Pikachu is next to the plate of food while Eevee is one centimetre away from it, but in the next shot, he is two centimetres away from it while Eevee is three centimetres away. (00:09:48)
The School of Hard Knocks - S1-E9
Revealing mistake: In the English dub, when showing the front of the flyer, it has filler text that is not related to what it is about. Also, its Poké Balls are slightly transparent and its picture can be seen through it. (00:05:43)
Pokemon, I Choose You! - S1-E1
Other mistake: When Pidgey turns its head to see Ash with a Poké Ball, its head feathers beside its eyes are mistakenly coloured cream instead of brown. (00:11:36)
Island of the Giant Pokemon - S1-E17
Continuity mistake: When Jessie says, "Well, you can use a good workout," the window frame in front of her and James is black, but in the next shot, it is instantly cream. (00:13:31)
Plot hole: After Ritchie tells Misty that he never talked to them through a phone, Misty could have put two and two together and realised that Ash was told to go somewhere by someone impersonating Ritchie and that he might be in serious danger. However, she does absolutely nothing to help Ash, she doesn't even inform Brock about it.
Bulbasaur and the Hidden Village - S1-E10
Other mistake: In the scene when Team Rocket tries to steal the Pokemon, Bulbasaur saves Oddish. Ash comes to help push Bulbasaur, and for a few frames you can see 2 sets of hand prints cut out where Ash's hands go.
Continuity mistake: Jessie seems completely surprised when she's told that Voltorb can explode, but in The Ninja-Pokemon Showdown (Season 1, Episode 32), not only did she and the others find out what Voltorb are, they were all affected by the explosions as well.
The Fourth Round Rumble - S1-E77
Character mistake: When Officer Jenny orders her Growlithe to attack Team Rocket's balloon, she refers to Growlithe as Arcanine. [This mistake happens only in the English version. In the Japanese version she refers to Growlithe correctly.]. (00:12:21)
Character mistake: When Team Rocket first sees Mandi doing his magic tricks, he produces a bunch of Pidgey. Meowth says "I like those Pidgeotto." He's dealt with Ash's Pidgeotto on numerous occasions, so there's no reason that he shouldn't be able to tell the difference. [This mistake only appears in the English version. In the Japanese version Meowth doesn't even mention Pidgey nor Pidgeotto at all.] (00:04:49)
Continuity mistake: When Jessie says, "Guess we woke up this sleepy dump," she has lipstick on, but the next shot shows her immediately having no lipstick. (00:12:22)
