Here was their response. I responded back telling him that it is happening on multiple providers in HD and SD.
"It is FOX Sports mission to always provide our viewers with the best possible game coverage. One of the new features we are providing to our standard definition customers is a letterbox live feed so more of the game can be seen on the screen at home. While we have had many recent conversations as well as given ample instructions to cable providers across the country, some are continuing to augment our live game broadcast. We thank you for bringing this to our attention, if you could please reply back with the your zip code and cable carriers name we will contact them in the coming week to ensure they are following the proper handling instructions of our live broadcasts going forward"