(I'll have to make a 'jiggler' to keep it from screensaver mode until then)
From what I'm reading, that is intentional. In other words, a change in how it performs, not a bug.
I would suggest to Roku that changes like that be made optional via a menu setting. Users learn how the devices operate and establish behavior based upon that that best suits the user's particular wants and needs. When device behavior changes, that will upset the user's routine on a varying basis. Since I commonly return to the Home Page, it's not something I would have noticed. However, for you, it's a major change. And a menu setting to turn on/off such behavior would have been a better implementation.