Report a television reception problem with only a single cable channel

I want to report a television reception problem that affects only one cable channel (MSNBC). It occurs on every live program broadcast and only under specific and very frequent circumstances. Normal audio/visual reception is good, however there is an extreme amount of audio 'cutting out' whenever certain types of graphics are posted. The worst is when newspaper headlines, quotes, or other types of documents are posted while the host is simultaneously reading the content. Words get clipped or cut out entirely, making listening unintelligible and frustrating. I can provide a couple of very brief (seconds long) iPhone videos from recent broadcasts if that would be helpful in determining if this is a coding or transmission issue from either MSNBC or Xfinity(Comcast). FYI, unplugging three television units and cable boxes from power does nothing to rectify the problem. MSNBC is my news channel of choice but it has become nearly untenable to watch. I hope the problem can be identified and rectified quickly. Thank you for your attention to this matter.