Little Box of Horrors - S7-E18
Character mistake: Katya (as Nina) says that Pandora's Box is "a gift the gods gave to Prometheus." But the Box was given to Epimetheus, not Prometheus. Epimetheus ignored the warnings of Prometheus, his brother, and accepted Pandora herself, who bore a box, as a gift from the gods.
Character mistake: When Charlotte is looking at her wedding announcement in the New York Times, there is a close-up shot of part of the article. It says, in reference to Charlotte: "She is a writer and editor at Fashions Magazine in Manhattan". This is not true, nor has it ever been true. Perhaps the producers of the show threw that in, to see if anyone would notice. Also, the same article mentions: "The bride, who will be keeping her name..." and yet we never really hear Charlotte use the name York instead of Goldenblatt. (00:16:45)