@YouTube heads up, your smart TV apps no longer respect user settings. I've opted out of all auto-play everywhere I can, but you continue to auto-play a random list of music videos if I watch through your official smart TV app on Samsung devices.
Appreciate your efforts in trying to fix it. Please send a feedback report directly from YouTube: https://goo.gl/WdI0BK . While every individual report may not get a direct response, we do review everything and use the details to investigate and fix issues.