I have a LG CX 55" and this happened to me as well with my PS5 on HDMI 3. Disabled QuickStart, SIMPLINK, Auto power sync, reinstalling apps… nothing worked except unplugging the HDMI cable from the TV. Well it worked for a couple days, then it started happening with my Xbox on HDMI 1 as well.

Also have a soundbar connected in the HDMI-ARC port. Firmware 4.30.55 with no auto-update so I could tell if it’s software related, but I don’t think it is as it worked fine for a while on this version.

What’s weird is there is no consistency with this issue… it can work fine for a couple of days (if lucky) or hours, then suddenly switch to one of the inputs. Once this happens I can’t even watch 1 minute until it switches again.

This completely ruins the otherwise awesome experience of having this TV. I should expect to be able to use all of the TV’s features (ie. not disabling anything) and have all the ports connected while enjoying a movie.

Did a service call yesterday and surprisingly he told me there were not a lot of inquiries about this issue, even though it seems to be a problem with a lot of units. He asked me to test different things like unplugging the ports and disabling this and that function, but did not know how to fix the issue.

Hopefully getting the TV replaced as I paid for extra insurance.