Guys!!!!! quick fix!!! Re-Connect your smart tv remote - Auto function in tv is to keep scanning for new remotes if disconnects...for some reason the tv tries turning on and off as a way of trying to re find a remote... hence no controls/constant on/off!!! i bet if these are your tvs problems this is the way to fix it!!! bugger paying heaps for techs n bull dust.. take your batteries out. put them in again and re connect them using the instruction booklet! so dam easy problem solved instantly.
Samsung is fixing the problems with the 2018 Q8FN models. They reproduced the problem using time stamps and picture settings we gave them in another thread and by email.
Hopefully the next firmware update fixes the restarts, improves the local dimming and takes care of some of the motion problems.