Setting Last input or Power On Input to be a Smart App

[Mpd-nbc]

 Finally giving up my STB's.

Trying to make the turn on input YouTube TV (or at least the Last Input) on my UN28M4500AF.
It will not obey the Last Smart App setting.Software says it is Up to Date  

Even tried removing the HDMI feed.  And it still defaults to that missing input. 

It works on my newer model. (granted a whole other animal) QN55 Frame TV

Anybody know a “hack” to do so.