For some reason, I found that the ARC being assigned to a different port.
You guys can try going to All Settings > General > Devices > External Devices > Universal Control Settings
Select HDMI 4 (where I assume we have our sound bar / device connected). Click Manage Settings.
I found there what HDMI port ARC was assigned.
I moved my connection to my sound bar/device to that port… and it worked for me.
I am guessing a patch on this is on the works in LG as I am sure there is a reason why Arc/E-arc is labelled to be HDMI 4 on the TV.
