There are lots of people who can't remember other people. Especially when they meet them in another situation (like when they are out shopping wearing casual clothes etc.). He probably just thought she looked unusual, then threw it in the back of his head since he wasn't going to see her again.
But her coloring is unusual for the area that she's in. He even states that he's never seen her coloring before, and he should have a doctor's of where all the people he sold as slaves went, especially since she was the only princess he let live. He doesn't cross me as someone that would forget those types of details.
That was supposed to be documents, not doctor's
to be fair he probably assumed she d be a useless crying mess like "all the other royals" would ve been, he might have trouble connecting the face cuz she s actually doing pretty well despite her circumstances
Okay, honestly, she doesn't look that damn different, how can he not tell who she was. He fucking stared at her so many times, even made note of how unusual her hair and eyes were but not once does he put two and two together. Is he actually a dumb ass or what?