Lorna Bucket from “A Good Man Goes To War” had previously met The Doctor. Eleven did not remember her, but it’s still unclear if he had forgotten her or had yet to meet her from his perspective.
I think he forgot.
From “A Good Man Goes To War”
Amy- “He’s not a warrior”
Lorna – “Then why is he called The Doctor?”
From “The Night of The Doctor”
Eight- “Make me a warrior”
He proceeds to regenerate into a younger version of the John Hurt Doctor, credited as “The War Doctor”.
Lorna Bucket first encountered The Doctor when he was The War Doctor, perhaps even during the Time War itself. Perhaps he didn’t shed the persona of The Doctor as thoroughly as “The Night Of The Doctor” implied, even during his time as The War Doctor, and that’s why Elevens faked recounting of their adventures sounded right to Lorna?