No DVR functionality on some channels

I have a Record 6 DVR. I discovered that there are several channels where DVR functionality does not work. While watching one of these channels it will not buffer so I cannot Pause or Rewind. I can only watch in real time. If I try to start recording the channel, I get the normal prompts but no recording happens. Afterwards, the program shows up in the Missed Recordings section stating "Recording failed because we experienced some technical difficulties". If I schedule a recording on one of these channels, the recording happens without a problem. I can even Pause or Rewind & return to live while it's recording.

So far I've only discovered this occurring on about 8-10 channels. There may be more but I haven't tested every one. On most channels everything works as expected. There is over 50% free space on the drive. I've tried resetting box several times. The problem still persists. Since this is only happening on certain channels, it suggests it's a software glitch opposed to a hardware problem. Is there any way to fix this short of replacing the box?