What is the "Top Box"?
The Roku itself.
I turn off the TV (with the Roku remote). It also shuts off the Roku (top box). When turning back on TV (with the Roku remote), it turns on TV, but not the Roku (top box)
So you press the power off button on your roku remote and it turns the TV off and the Roku somehow powers off? But then pressing the button again turns the TV on but the Roku is still "off"?
That's super strange as the Roku doesn't have an "Off". What happens if you turn the TV off using the TV's remote? Does the Roku then turn "off"? If so, then there must be something with CEC.
Are both of them plugged into some sort of smart power strip where the TV turns off the other devices on the strip?
That power key on the remote is strictly for TV's, there is no roku power command available. If some how its powered via TV usb port or plugged into switched outlet? Try turning off hdmi cec in the tv menu.
Thanks all, seemed to be HDMI port related.