The "LiveTV on the Roku Channel" tile icon is basically a shortcut so users do not have to launch the Roku Channel first in order to get to the LiveTV. Of course, with the Home Screen menu on the left side, the "LiveTV" menu item (if enabled to show on Home Screen) will perform a similar function.
This tile icon has been around since OS10 or 11, I believe. I have had it on my devices for awhile.
If using the * button is not working for you to permanently remove this icon, then try performing a Search from the Home Screen for "Roku". Locate the "LiveTV on the Roku Channel" tile icon from the Search Results, and select "Remove" from this menu.
Then try performing a System Restart and see if it returns.
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I just removed mine with the * button and it stayed removed after a System Restart. Same build as you mentioned on an Ultra 4660x.
