Transylvanian Homesick Blues - S2-E65
Character mistake: Ray says that it's the very first time they've dealt with vampires. In Season 2 Episode 25, "No One Comes to Lupusville", the Ghostbusters had to deal with both werewolves and vampires.
Doragon! Muteki no ken to tate - S1-E4
Character mistake: Shun says explicitly that a Saint's body is no different from any ordinary human's. That's quite funny, considering that in the previous episode Hyoga fought creating temperatures of -100 °C (consistently, to defend himself, and aggressively to freeze Ichi), which would have messed up really badly both contestants.