Thanks for the post.
Try removing the channel from the Roku home screen by navigating to the channel tile, pressing the * key on your remote and choosing 'Remove channel'. Then restart your device from Settings>System>System restart. Once your player starts up again, add the channel back once more. Does this clear up the issue you are seeing?
In addition, have you tried switching out the HDMI cable or using another HDMI port on your TV?
Please keep us posted.
Roku Community Moderator