I'm having the exact same problem (on the same channel) on one STB, the other 2 are getting the sound just fine.
However, on one of the other STB's I lost the HISTORY channel altogether. I still receive it on the other 2 STB's.
Does anyone have any idea on how to correct these problems?
A solution would be greatly appreciated.
RE the problem with the missing history channel, turn off and unplug the STB/DVR. Wait about a minute and then plug it back in, but do not turn it on yet. Wait for the box to initialize (the time will eventually display). Turn on the box and check if the problem is corrected.
Hope this helps