>>2340536>A girl who is afraid of social contact will no run screaming from the room, she'll nervously reply and hope the other person fucks off.I can't remember that occurring outside of Act 1 and Shizune's route due to her pressing for another game. I think Act 1 was written by one person, while all the routes had their own writer.
Her behavior made sense during the following meeting with Lilly and everywhere else in my opinion.
You see her open up more to Hisao during multiple scenes and seeing her out and about in the city shows how she's getting more comfortable being surrounded by strangers. While she had walled herself off emotionally from most of the people at Yamaku, she still went on shopping runs and had to navigate crowded halls, so it's not unrealistic to see those changes take place.
It's only the reminder of her birthday and the ending where they both realize the mistakes they made that she breaks down. Both cases being understandable.