Yeah I tried that and it still flickers when i switch to Earc. When i do successfully have eArc on and is running.. I cannot switch the TV off as it then starts to flicker again upon switching it back on.
In that case, assuming both the TV and Arc software are up-to-date The only other thing to maybe try is changing the cable between the Arc and TV, but first leave any other devices disconnected from the HDMI ports 1, 3 and 4 and power off both TV and Arc at the wall for 3 minutes.
If the new cable doesn’t fix it then I suspect there maybe a fault either with the TV or the Arc. So go onto do the following…
Within 20 minutes of the issue occurring again, I would submit a Sonos diagnostic report from the ‘Settings/Support’ area of the Sonos App
Make a note of the reference generated and perhaps post it back here.
Then, when available, contact/chat to Sonos Support Staff about the matter via this LINK and see what they can suggest to try to resolve the matter.