I realise this is an old thread, but did any of the posters resolve this issue? I am having the exact same problem where I hold down the TV button on the ATV remote and press sleep. The ATV then goes to sleep and the TV turns off, however then the ATV wakes again after just a few seconds and stays awake, with the white LED staying on. I have found one work around, although its not really helpful in the long term. If I turn my tv off first and then with the tv screen off hold down the TV button on the ATV remote for a few seconds and then press sleep, the ATV stays asleep. I am using an ATV 4K, on tvOS 11.1, and a Samsung Q7 TV. Any help or advice would be appreciated