Are you sure you went to her BED ROOM in the EVENING? In your screenshot, it might be the Living room at night.
Because everyone who used my save and went to the correct place at the correct time of day had been able to trigger the event.
There are six times of the day in total: Morning, Noon, Afternoon, Evening, Night, and Late Night. Isabel is in her room in the morning (sleeping, can't interact), and evening (reading a book, this is where the event you want trigger), the living room at noon (cleaning, can interact) and night (sitting on sofa, can interact).