Sorry to hear that.
If it does it on all HDMI sources (not just the dish) then it's a defect. If it's just the dish then something is amiss in that area (part A does not work with part B).
I know consumers do not want to discuss how HDMI works but this is one of the areas you run into now and then. You see cable and dish and other boxes being changed out or the firmware in the HDTV or boxes changed.
The days of it just worked appear to be long gone.