Rebooting Roku fixes it temporarily. I had both black out screen, delay and split screen. What worked for me : 1. Press the Home button on your Roku remote. 2. Scroll up or down and select Settings. 3. Select System and then select Advanced system settings. 4. Select Advanced display settings. 5. Select Auto-adjust display refresh rate and choose: DISABLE.
Your Roku player will then output ALL content at 60fps. If it is ENABLED, Roku tries to adjust to the native format of the movie, video or TV show. I actually had the problem after choosing ENABLED to try to sync audio. When I changed it back to DISABLE, the problem went away. This can be a problem with Netflix. The split screen kicked in while I was watching Newsy and then did not go away when I went to other channels. It stopped when I reverted back to DISABLE as outlined above.