Welcome to our Community and thanks so much for your post - I was sorry to understand that you've had some issues with some of your HD channels recently. Is this only on the sports channels you've noticed this issue and does a reboot help with the picture quality at all?
I have located your account and can see you have 2 boxes with us; are you having the issue on both boxes? I can see one box was rebooted a couple of days ago and the other has been over a week - other than that all seems to be looking ok at the time of writing.
We have no known issues reported for the fault you advise and when checking the services from here the picture quality seems fine. Was this happening on any particular show?