Page 4: The box is titled "The True Nature of The Hyborian Age" but the first phrase after the title is "Emphatically not."
This is the reply to the title of this box in the 1st edition of Conan (it was: "Is the Hyborian Age a 'Low Magic' or a 'Low Fantasy' setting" instead of "The True Nature of The Hyborian Age"). It has no sense in the Atlantean edition (IMHO or the title must be changed back to the original, or the first phrase must be cancelled).
Page 162, Image "Taking a five-foot feet": I'm pretty sure I saw a post from someone from Mongoose saying that text in the figure about Valeria avoiding an attack of opportunity is wrong, but I haven't bookmarked the post.
Page 310/311: The same text (the entire subchapter "Cobra or Viper" is printed on page 310 (in the main text) and on page 311 (in the box)