Stop Roku "Auto-Play"

I see this happening quite often. I’ll have been watching Netflix via Roku, then turned off my Samsung TV. Next day, I turn on TV and watch cable for a while. If I then switch to Roku, it is in the middle of playing a movie from my Plex server. Typically, it will be whatever last movie I added to my Plex library.

I’ve disabled CEC on the Samsung TV. I don’t see that Roku has an option to “auto-play” and I don’t see Plex having a setting for “auto-play” either.

Any idea how I can turn this off? Thanks.

I had an issue similar (not the exact same) with my mother and Roku still playing after shut off. The only way I could find to stop it was to purchase an Advance Power Strip that shuts off the Roku when the TV is shut off (like when the sleep timer on the TV is used).
Might help?