I think this might be happening because of the Siri remote. I notice that my remote seems to generate phantom taps on its touch surface that cause the Apple TV to display its video overlays. This happens even when the remote is sitting by itself, untouched for many minutes on a table. I've also noticed that the touch surface will often stop working while I'm watching a video until I click a button on the remote, so it looks like the touch surface can have states where it is too sensitive or completely non-functional (asleep?). Basically, in my hands (literally) the touch surface doesn't work very well.