Just published my video! https://www.youtube.com/watch?v=U6VP2KFQi6k
I had this happen with my Fire TV. If I left the Fire TV on at the home screen... the TV would invariably eventually turn back on. If I launch an app or put the Fire TV in sleep mode, the TV stopped turning on.
It's pretty annoying and hopefully something Samsung can fix.
It's not the cable company for me because I don't have cable. I have a ps4 and a chromecast and that's it. I think the real problem is the arc and people's sound bars. I replaced my sony sound bar with a samsung one and the tv hasn't turned on by itself since then. So 4 days straight with sony my tv turned on several times during the night. For the last week with a samsung sound bar it hasn't turned on once. So for me it was all about the arc input and the sound bar interaction.
I would have to agree that a common denominator is the HDMI-CEC device(s) connected to your TV.
Yesterday, I updated the firmware of my Bose soundbar OTA from within its app. The TV turned turned on when the update commenced.
It would seem that the CEC device sends a 'power on' signal to the TV because the device itself is powering up. Normal (expected) behaviour in my situation.
So, whomever it was that pointed out that an auto-update being sent to your set top box (that is connected by HDMI-CEC) is probably right. The TV is doing what it's supposed to when the connected device turns itself on and the TV stays on, unless you have it set to automatically turn off after a set period of time. For some reason my cable box does not turn on when the cable company pushes updates to the box, so they must vary by device.
Unless someone knows an HDMI-CEC workaround, the only alternative I can think of is to connect via TOSLINK (optical). Not the advice anyone wants to hear, myself included.