Just seen this over at /r/disneyplus so thought I'd share. Works for me now on my 50PUS8204. Still no Atmos though. Which is funny, because the reason I checked the subreddit was because of this post .
Also. After the TV updated there was an update for the built in Chromecast. And now I can't cast anything to my TV. I love you Google.
Edit: uninstalling the Chromecast update and reinstalling has fixed it...I think.
Woop, thanks for the crosspost. Updated my 55OLED855 and so nice to have dolby Vision back!