Is this a new one? I don't remember it being mentioned and searches haven't turned up anything yet...
In the prologue to The Butlerian Jihad, Irulan says she will tell "the story of free humans rebelling against the domination of robots, computer, and cymeks." The prologue goes on to detail the rise of the Titans and their conversion to "cymeks". Agamemnon is mentioned BY NAME repeatedly. Irulan also specifically refers to "the current jihad that followed the overthrow of my father, Emperor Shaddam IV", establishing that the time of writing is during the Fremen Jihad, in the period between Dune and Dune Messiah.
Later, in Children of Dune, Irulan doesn't seem to know who Agamemnon was, or to even recognize the name, when Ghanima mentions the Greek king and Atreides ancestor in passing.
Did Irulan go stupid? Or did the hack(s) fuck up on another little detail? (I think this one is a stupid, careless mistake rather than an intentional change like "Paul born on Kaitain", because setting the time of writing during the Fremen Jihad doesn't really make any difference in the McDune story.)
I have heard of only one mistake that doesn’t have an explanation for a careful reader...with an open mind. (And, no, I’m not going to tell you what it is!) —KJA
I don't like every writer's style; for instance, I have never been able to get through Ursula LeGuin, China Mieville, or Iain Banks, all of whom are critical darlings. —KJA
I...had written a bunch of Star Wars and X-Files books...that proved not just that I'm a hack, but that I could write in somebody else's universe... —KJA