[Joedm45]

One random theory on this:

The box rebooted itself at some point between the show finishing and the recording finishing? When it came back online there was nothing left to record
That way you would be none the wiser as you've watched what you need to but the box counts it as a failed recording and automatically records the next showing for you.

A bit out there but could be possible. It may be too late to check now but if you have one or more tuners on channel 999 then that signifies a re-boot took place.