A couple days ago, I posted a topic where, for some reason, the YouTube app for Roku stops playing after a few hours. Most recently, someone replied to my situation stating that the best way to take care of it was to set my "Bandwidth Saver" settings to "OFF". I thought it worked, but I've come across the same issue (although I'm tempted to say it lasted longer than before; I was there to witness it, just for good measure). I honestly don't know what I'm doing wrong, if anything.
If any of you have any further questions or concerns, do not hesitate to ask.
Note that the Bandwidth Saver setting will stop the Roku after four hours with no interaction. You will be prompted by an overlaid message asking if you're still watching. That's a Roku function. As you've disabled that, you won't get that from Roku.
However ... that won't stop any individual app from acting that way. And it seems YouTube does that. Note that I never use Autoplay on any app, so I've never encountered that. However, searching on the Internet finds that YouTube does indeed do that itself.
YouTube will ask if you're still watching after around 5-6 hours, from what I'm seeing. It pops its own "Are you still watching?" kind of thing, according to some online sources.
What that means is that Roku is no longer doing it, as you've disabled the Bandwidth Saver, but now you're running up against YouTube's version of the same thing.
You may want to find a different source if you need more than 5-6 hours straight videos for cats. You might want to look into something such as Pluto TV as an alternative.
DBDukes http://www.dbdukes.com/Roku Ultra (4660) Roku Streambar (9102) Roku Streaming Stick+ (3810)