I have 3 roku1's as of Aug 3rd they
all like clockwork in 20 to 30 minutes back up to the main page. On Netflix, Hulu, Amazon, basically everything in the channel store I use. I have done factory resets on all of them, tried all the other stuff first. . The cable company came out checked all my stuff, router, checked wires, speed etc. I thought maybe it was because my rokus are older, but obviously if it's doing it on the Express theres more to the problem. After the cable company came out I figured it was fixed. Nope not at all. Roku needs to get this figured out
If this is happening during active streaming then it is a bug somewhere BUT if it is happening when the Roku is idle then it is expected and designed behavior.
FWIW: I pretty much watch TV and movies on my Rokus whenever I am awake. I have, with age, become somewhat mobility challenged and there is little else to fill the time. My Rokus do return to home screen if I am at any menu in any app but it does not seem to happen if there is a stream active, even if it is paused. The longest I leave my Rokus paused is about 45 minutes to an hour so I cannot attest to the behavior with longer pauses.
I have Roku Ultras so the behavior "might" be different for Roku 1s.