Character mistake: Art expert Dale Kingston describes Goya as 'the penultimate artist'. "Penultimate" has nothing to do with greatness or artistry, it means second to last, and nowhere during his speech does he indicate that Goya is 'second to last' in anything to do with the discussion. In the context he uses it the word is completely meaningless.
Six Strangers at Apache Springs - S2-E7
Character mistake: Preacher quotes from the bible ("The harvest is past, the summer is ended, and we are not saved") stating it's from Jeremiah chapter 9, verse 20, but she quoted Jeremiah chapter 8, verse 20.
Character mistake: Edith says in a story that Archie has a brother Phil. In actuality Archie had 1 brother, Fred.