For those who were conflicted by HY βYESβ answer. It was bc of the mistranslation of XJ question. It actually translates as WERE YOU LATE DURING THE BATTLE OF MINGSHUI. girl was just telling the truth.
Upon reading previous comments and seeing the teaser for ep22-23, her identity as Gen FH will be known to XJ, and the writers decided to make it a misunderstanding between the 2. And it happens before her identity as female will be known to all. They just re-sequence the events from the novel. Interesting. How it will unfold