When reading, and to some extend also watching movies or series, there are sometimes inconsistencies. Something doesn't add up, or things don't quite make sense.
Sure, it can be that I have just missed something. Or even forgotten. It's hard to say without redoing revisiting the whole of the preceding story.
Those writers are people too. And mistakes happen. It can very well be the details were there in their head while writing. But it just slipped their mind when writing about it. It's same with every writing task. It's hard to see things missing when you write because you know all the facts yourself. You don't notice those missing pieces.
For fiction, while annoying it can be forgiven. The ides of storytelling is after all that the reader/viewer can fill in the holes. So why not fill those obvious illogicalities and plot holes as well. What is left untold is the responsibility of the reader. That is the art of storytelling: everybody can make the story their own.