I don’t think there’s any irony in the French version – the basic meaning is “and there’s nothing new in that”, isn’t it? On that basis, if there’s no mistake then it’s the English version that’s non-literal. Like Greg, I think the mistake hypothesis is far more plausible. You do find translation mistakes even in books from major publishers. I have one in which the English word “score”, used in a musical context and meaning “partition”, is translated as “résultat sportif” – so things do, um, slip through the net.