Honestly, while I do sort of agree, it's really not. Consider how much he has in his head. He also knows where the story is going so he has ideas for what's to come and I'm sure it's easy to lose track of what's been published and what's still conceptual.
What I think is interesting are the answers that are more philosophical where he says that person X from the world would say this is happening, but he (Brandon) is not convinced. I mean, shouldn't Brandon know how it works if anyone does?