Thanks for the post.
Do you current have any volume modes enabled on your Roku device? Do you have audio leveling on? If so, have you tried disabling them to see if that helps the issue you are seeing?
With more information, we will be able to assist you further.
What is the point in @healthchic posting any info? Why don't they just not use those channels? Seems like that is the solution to the initial problem in this post!