She operated on a simple principle. To those who treated her well, she would return the favor. To those who showed her hostility, she wouldn't bother to curry favor.
Norah knew Jolie had only pretended to care about her. In fact, Jolie had been speaking badly of her behind her back in the hospital's group chat.
After Norah discovered this through a monitoring tool she had set in the group chat, she realized Jolie's animosity might stem from envy over her growing reputation and favor with Jamison, prompting Jolie's negative comments.