she posted a post on tumblr about it, I did look at the proof post she linked to for her fanfic and by the looks of it, it's human writing as I don't think ai does edits or things like that, and her fanfic reads like her IF so maybe it is real and just overthought. I've never used ai so I really could be wrong but it seems pretty human in method if not in actual writing.
I'm glad she posted about the ai accusation rather than ignoring it like some authors do