You must have progressed far enough with both Linda and Emily. You need to have the sleepover scene with Emily, in which you are caught by Linda. After that, keep talking to both of them throughout the day. (By the way, Linda needs to be in her regular clothes (black and teal).)
Visit Linda in the living room in the morning, and the first scene should play automatically. Emily walks in on you both. Try finding and talking to Emily throughout the day.
The next day, during daytime go to the living room to trigger the final scene of this update.
