My Roku ultra Lt was returning to the home screen constantly, it was unusable. I returned it and got a new, the new one did the same thing, not any better. One day I noticed my Roku scrolling through channels without me touching anything so I removed the batteries from the remote and paired an old Roku remote I had at home to the Roku ultra Lt, it has never returned to the home screen again, THE REMOTE IS THE PROBLEM, it thinks you are pushing buttons when you are not.
Good feedback for others to see a potential resolution when their apps return to home and they get occasional scrolling.
You should probably confirm by putting batteries back in and using the original remote again (and their might also be a remote firmware update) - if it starts happening again you know its the remote (perhaps pursue warranty replacement as well if its within warranty).