This app still takes a long time to load and when it finally finishes, I sometimes get a black screen. I then have to start over again and when the picture appears, the "centerpoint" of the movie moves to the lower right hand part of the screen. I have my TV display set on Auto.
Also, some programs (say, Oprah's interview show) is jerky/stutters, it looks as if frames are missing. When this happens, the audio and video are way out of sync.
I don't know why it's just the Apple TV+ app; all other apps work just fine; Prime Video, Pluto TV, Vudu, and all of the others work fine.
The Apple TV+ app needs some serious fixing of the bugs in it. It's no wonder they are rated the lowest service.
Re: Apple TV+ App Does Not Work (Still !) 09/13/2020
When there is a problem with just one channel app, it may help to reload the channel:
Highlight channel on home screen.
Press * key and choose Remove channel option.
IMPORTANT- DON'T SKIP: From home screen, Settings > System > System restart (or on a Roku TV Settings > System > Power> System restart). This assures no remnant of the old installation remains in the Roku's memory so you get a complete reinstall. It may or may not make a difference, depending on what's causing your problem, but it's worth doing.
Reinstall the channel.
If channel requires a login, you may need to log in anew.
Note that a reinstalled station gets added to the bottom of the channel grid on the Roku home page.
Roku Streaming Stick +, 3810X, Ser YH0059427035, wifi - Samsung UN55ES6100
Roku Streaming Stick, 3600X, Ser 5S56D8240827, wifi - JVC EM37T