My guess is actually on something silly and simple.
Like the ancestor telling her that if she keeps going on like this, she will lose the race. The proverbial kick in the behind...
Or it could be some sort of silly thing about powers, which would cement Narae as being the unlikable heroine that never stops with the violent all through the manga.
Maybe being possessed by a goddess dispelled some sort of horrendous curse she's been suffering from the whole series?? That has to be it. Nothing but a curse could excuse her behavior until now.
meek non violent Narae is a QT.
I suspect her sempai and clan mistress gave her a bit of a reality check about her role as a concubine in the phantom king's harem.
It would be very nice if the other bear girls told her to stop acting that way or she'll lose Sunghoon for real, but I fear we'll see violent Narae back soon.