So with Halo Reach and having to get Cortana to the Piller of Autumn we all felt it went against the books.
However according to 343’s decriptions of everything in the universe section, there was this little snippet in with the Cortana profile.
“After the Covenant had begun their assault on the planet, Dr. Halsey employed Noble Team to reunite Cortana’s fragment with her primary presence with the Master Chief aboard the UNSC Pillar of Autumn. SPARTAN-III B-312 made the final delivery, and Cortana and the Master Chief made their escape off Reach, via a fateful slipspace jump that took them to the first discovery of the Forerunner ringworld known as Halo.”
So they understood that what Bungie did with Reach went against the books and they incorporated it in that it was a fragment of Cortana.
It’s not something major, just something that always bugged me. Just glad to know they didn’t ignore it.