Yes, we have a similar problem with KVIA HD shows. We first noticed it around the time of the 2012 Academy Awards Ceremony on March 2. It's especially noticeable during music, such as when Idina Menzel was singing "Frozen," because the continuous music gets broken up. And yes, the audio "hiccups" are very frequent, usually multiple times a minute. I have a Pioneer VSX-1121K AV receiver that we process all of our audio through to surround sound speakers. During these audio glitches from KVIA, the AV receiver's display which normally shows "THX Surround EX" when it's receiving 5.1 channel input from ABC shows that we watch, such as "Once Upon a Time" and "Revenge," will briefly change to "Dial Norm -10" (or some other number). According to Pioneer forums, this Dialog Normalization is part of the Dolby Digital specification and is a value embedded as metadata in the broadcast signal, and the receiver makes adjustments to DB output based on that value. Here's what Pioneer Tech Spt told another poster: "Dial Norm -4 referring to Dialog Normalization which is a feature of Dolby Digital. Dialog Normalization Attenuates programs based on the average level of dialog in a program relative to it's peak level (also known as Dial Norm) in order to achieve a uniform playback level." So it appears to me that there's enough fluctuation of some sound component of 5.1 audio streams being broadcast by KVIA that this metadata value changes every 15 seconds or so, or else something is injecting spurious changes to that metadata value in the broadcast signal.
To see if the Pioneer receiver was part of the problem, I temporarily moved the HDMI cable box output directly to the TV and could hear the periodic glitches then, too.
We get the KVIA signal in Las Cruces through Comcast, but it's the only channel with this problem, and when I saw your post, I realized that it was probably coming from the source. I called KVIA this week about the sound quality and will send them an email message with a link to this forum. Although they haven't gotten any other complaints, it's a real issue to me. Maybe we can get to the bottom of the problem and get it fixed. They have some of my favorite shows.