Have you ever listened to an author in a live interview stumble over details of their own stories? Does it seem odd that the very creator of the fiction doesn’t know the story nearly as well as the fans?
Sometimes, the answer is simply that fans can be, well, fanatical. Star Trek in particular spawned such a devoted following, they even come up with elaborate explanations for those picky details that don’t fit into the grand scheme. Like in the movie Wrath of Khan when the bad guy addresses Chekov saying “I never forget a face…” fans were quick to point out that Chekov was not in the episode where the Enterprise found Khan in the first place. Walter Koenig (who plays Chekov) likes to explain Chekov was in the Enterprise bathroom for half an hour while Khan was waiting to use it and Khan swore never to forget him! Fans came up with the theory that Chekov was on the Enterprise, just not part of the bridge crew at the time. Perfectly reasonable.
Writers had nothing to do with these explanations.
Sometimes, the writer is at a loss because instead of just having the finished story in their head, they have every perturbation and twist and rewrite rattling around. They know what the characters were going to do before some editor decided it would be better if they did something else. The writer knows little details of the characters’ back stories that never made it to page or screen.
Last night, I finished the rough draft of Under the Radar. Although I like the story, I can tell right now that the finished product is going to look very different from the mash of words I have recorded right now! And someday, years from now, I’ll be talking to a fan, and they’ll ask me something like “But didn’t Scharona do ____ first?”
I’ll have to pause for a moment, and think back through the revisions, and more likely than not, my answer will honestly be “I don’t know… you tell me?”