I don't really like replying to threads that I've formally backed out of, but this one apparently isn't dying.
Though I largely support Source, on that part I agree that it's a bit iffy but I'm not sure if we want to read into it too literally. Definitive source or not, people make mistakes and there's a few areas where that's clearly done in the book. Especially glaring is the mistaken date of Midular's assassination, where the book claims it was in 113 instead of 115--I don't think anyone here would argue that that was an intentional retcon of the date. It's probable that the writers didn't really think about the implications of that line.
Has anyone asked one of the writers for clarification on if that was the intent? Source is intended to be the baseline moving forward, but it's very, very easy to write something thinking it means one thing only to have it imply something else entirely. I've considered sending a PM about it myself, but I'm not sure I'd be able to phrase the issue as well as other people have.
Of course, if it was intended to be read that way then I have to agree that it was a bad change to make.