Same problem here - here is my exact post on the issue, says the same thing only with a little more detail. I also posted this to a Roku support blog, and they say it is Apples App that is the issue, and has nothing to do with their box, and I believe that. Here is my original post...
I had recently installed Apple TV on my Roku 3 4200 X, and everything went well and I was able to watch anything I wanted, including apple plus shows. Starting today, when I select Apple TV from the menu, it briefly flashes the Apple TV logo on the screen then goes blank and won't do anything... it totally crashes the Roku box. When I press the home button, all the channels are just flickering on the screen and won't properly load. I can either reset the box, or navigate to one of the other channels, and even though it's flickering and you can't read it, if I choose it it will load nonetheless, and then I can back out of that and everything looks normal again.
What have I tried? I have deleted and reinstalled the Apple TV app no fewer than six times. I have made sure that the Roku box is completely up to date. I have removed the SD card, then rebooted and reinstalled Apple TV. Every time I uninstall the app, I also reboot the system before I reinstall it. I have done a cold reset on my high-speed AT&T router. All other channels and apps on my Roku device work properly with no issues, its only the Apple TV app that crashes. I'm wondering if maybe there was an Apple TV app update in the last couple days, or a Roku update that's now causing this problem? I have a different newer Roku box in the other room on another TV and the Apple App works fine there. According to the system info screen, my unit is a Roku model 3, 4200X, running software version 10.5.0, build #4174-04 if that helps anyone. One coincidence here is that I signed up for a 7-day free trial that would convert to a paid subscription after the seven days, and this issue seems to have coincided with the expiration of my free trial period… I thought I should include that information just in case it matters. Sure hope somebody has the answer to this issue...