Two of my four local stations have out of sync audio problem (WDBJ-CBS and WSLS-NBC). Watching Merlin on NBC a week ago was like watching a foreign movie with dubbing. Audio problem on WDBJ is less severe but consistent. Audio on WSLS goes from perfect to 'foreign movie'. Neither WSET-ABC nor WFXR-FOX have this problem. It seems that only 1080i channels are affected. Should I contact local stations or Dish?