1. Be sure the TV has LG's latest firmware. I can't keep up with all the models and methods but follow LG's instructions on this.
2. Turn off HDMI CeC (varies a little by name.) This can be some HDMI device sending a command and messing up.
3. If you can find the IR receiver on the TV. Block it with a book or something solid.
My LG smart TV changes channels back to the last watched and will often do this unbidden several times an hour. When I check "info" the selected channel still shows but the TV is displaying the last channel. I thought it was my Verizon Fios remote, and removed the batteries to test the theory, but the TV is still doing this and flipping channels on its own. Any suggestions?