I have an LG tv and the exact same thing is happening to me, it blocks captioning which we use and the screen. Every 60 seconds and you have to manually turn it off. I’m getting really frustrated that I’ve been searching and searching how to turn this off, and getting nowhere. Just started maybe Saturday night.
every 90 seconds on left hand side if screen a box shows up that says Roku TV followed by icons that say Tech Specs, Simple Home Screen, 500,000 Movies, Search and Free Roku Mobile app.
it's a Roku Element TV
Same answer as above. Your TV is in store mode, or it might be labeled demo mode. Search the settings menu and you should find it.
Dan Roku Stick (3600), Ultra (4640), Ultra (4670), Ultra (4800), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.