The HPNA light is only on if a device is using that connection, usually a STB connected via coax (can be over twisted pair in rare situations like apartments). It sounds like your setup uses ethernet which would not turn on the HPNA light.
The previous scene is an excerpt from Brain on Fire: My Month of Madness, and just one of many hallucinations Susannah Cahalan experienced in 2009 during her month-long hospital stay, in which she was diagnosed with a rare neurological autoimmune disease, known as anti-NMDA receptor encephalitis.
Brain on Fire by Susannah Cahalan - review. Paranoid hallucinations: Susannah Cahalan was lucky to find a sensitive doctor who listened to her. One morning, Susannah Cahalan woke from dreams of bedbugs to find two red dots on the main vein in one arm. She called an exterminator to comb through her Manhattan apartment; he found nothing at all. But bedbugs had been in the news, and danced insistently through her mind, and she could not believe him.