Just happened to stumble across this thread.
Just to explain/clarify a bit. These TVs with HDMI inputs will normally have some some form of HDMI CEC control. This CEC control allows a device connected to an HDMI input to perform certain functions. (ie dvd player to automatically wake and switch to the appropriate HDMI input port when a remote button is pushed.)
Depending on the manufacturer of your TV, this HDMI CEC feature may be named differently. You access the HDMI CEC under Settings using your TV remote. The different names for HDMI CEC can be found at this link. https://hd-report.com/hdmi-cec-by-tv-manufacturer/
The One-Touch Play feature of the Roku allows you to wake and automatically switch to the assigned HDMI with the press of any of the Roku remote buttons. (any button press turns both Roku and TV on, and switches to HDMI). If you disable One-Touch Play, and have the Roku remote programmed to control your TV power and volume, you will need to press the Power button on the Roku button to wake the Roku and power on your TV. (other button presses other than Power will have no effect on the Roku or your TV when both are powered off.).
As both @rakwoka and @JaredAH correctly indicated, disabling these should resolve hijacked remote/hdmi issue. By disabling your TV's CEC, should automatically disable Roku's One Touch Play. On some TVs, you can configure the CEC capability for individual HDMI inputs as well. However, since HDMI CEC is useful to other connected devices, you should first just disable the One-Touch Play to see if resolves issue initially before disabling your TV's CEC capability. To enable/disable Roku One-Touch Play...
Settings..System..Control Other Devices... 1-Touch Play [Checkmark to Enable] [No Checkmark to Disable]
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