Overscan is off. Obviously if it's one then the noise frame is cut out.
My UI has been years ViV-Night-HD, I downloaded & tested 'Default1080' as well.
The ViX chance the TV display mode and UI is smaller and noise frame (or part of it) will be formed on the areas not lay-out by UI
On Picture&Audio menu have Auto resolution-All
If the value is Not in use i.e. the TV's resolution doesn't change based on original material the noise is not generated.
Was the Auto resolution-All with 5.x or -Not in use, I'm not sure. Though, I think that the noise frames are not generated by TV but ViX because restart of UI clears the screen.