Solving playback issues

[Weathervane]

One of our Roku Ultras will spontaneously switch from whatever we're watching (e.g., Amazon Prime) over to YouTube TV.  It happens across various providers and always goes to YTTV. As an experiment, I started watching a show on Netflix, then removed the batteries from the remote. Later, the Roku switched back over to YTTV on its own so apparently the remote isn't the problem.

What should I do?  The only other thing I can think of trying is a factory reset.

Model 4660X2

[renojim]

Since your Ultra will respond to IR remotes, maybe it's picking up some rogue signal that it's interpreting as "launch YTTV".  Try putting it in a box or otherwise blocking any possibility of light reaching it.