I have a Samsung UE55RU8000 TV with a Harman/Kordon Q60R soundbar. Pretty much everyday I have this issue that I put the TV on standby with the smart remote (the small one) and it goes to sleep for about 20 seconds and turns itself on again by itself. I noticed even when it doesn't turn itself on the remote's LED blinks couple times after about 20 seconds of the turn off command. Which makes me believe the issue is originated with the remote.
I tried number of things, connected the soundbar with optical cable instead of bluetooth and turned off anynet+ cec on TV as I also have a PS4 connected via HDMI. Still having the same issue. I'd be very greteful if anyone has a clue!
other devices and connections could be interfering with your TV. Please unplug all external devices, including the aerial, and disconnect from the Wi-Fi network (turn your router off). Re-connect the devices one by one, testing the TV each time, to see if this is still happening. This will help to identify whether an external factor is causing this.