@Phelix Or I could say "ultimately no", cause I doubt you messaged the author to ask them if that particular narration line was AUTHOR getting facts wrong or CHARACTER talking about something he doesn't fully understand.
Even if I were to say I agree with you, I believe you should dial it down a bit and go for "author prolly was lazy and didn't fact check". Which, as I said, I may agree with, this author doesn't seem too good, so it seems something likely to happen. But it's still just a possibility; there's the other possibility: the character being wrong, simple as that.
I mean, the argument is kind of moronic. "Yes because the informaton is still wrong". By that logic, no book or movie EVER can have a character EVER saying something wrong, cause boy, it's wrong information.
If it's not an educational work, it's up to the reader to gauge whether what they're reading is true or not. A character may be lying, or may be wrong. Dude, do you remember being a teenager? Saying something trying to impress a girl? You were probably wrong with what you said, but if it made you sound smart, you went for it. You can create such a character, and he will be wrong. Doesn't mean the author did or did not research.