Character mistake: Misty is notoriously afraid of bugs. She makes this clear whenever bugs are around. She seems to be okay with Tracey's Venonat, but for some reason doesn't think it should be classified as a bug, when its type is Bug/Poison, and it's quite obvious that "Venonat" comes from "venom gnat, " a gnat being an insect. She even directly states that "At least they're [Venonat and Marill] not Bug types!"
Character mistake: When Team Rocket first sees Mandy 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.