Apple TV App Pixelated Transitions

I buy a lot of movies through iTunes. I use Vudu, Movies Anywhere, and now the Apple TV app on Roku to watch them. Before the Apple TV app on Roku, I would watch a lot of the iTunes titles through a computer linked to my TV. I was very excited about the new Apple TV app on Roku. However, it's been very disappointing. A lot of times when the scene transitions in a movie, it's pixelated and even freezes. I have excellent internet speed (usually 40+ to over 100 mbps). Also, I never have this problem when viewing a movie through Vudu, Movies Anywhere, Amazon Prime, Netflix, Hulu, Disney, etc...only with the Apple TV app. By the way, I uninstalled the Apple TV app and then reinstalled it, so I know that's not the problem. Is this a problem others are having...some kinks you are trying to work out?