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).
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: In the opening scene, Doug call Carrie "Kel" which is Deacon's wife. He calls her that when he's saying they should just get a new grill.
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)
Character mistake: When talking to Will on the phone, Grace misuses the term "pied-à-terre" (which means "apartment" in French) instead of "pas de deux" (a dance for two) while describing the delicate and complex nature of a relationship between two gay men. When Will points out her error, she says she knows what pied-à-terre means because she took Spanish in high school. However, in season 1, episode 20 ("Saving Grace"), Grace correctly and easily used the term pied-à-terre while showing her sample book to a potential client.