My Contour 1 box does this all the time. I would guess that 1 out of 30 shows ends up in a Missed Recording. Most of them say that the program was not found in the Guide. Some say "this program was not recorded because it conflicted with a high-priority recording" which makes no sense at all. I don't have any high priority recordings.
I also get a lot of recordings that seem to be there; but when i hit play the screen is black. I get a message saying that the program is having trouble playing and i should try again later. Trying later doesn't work. Have you ever had that happen? I have started recording Timeless on the HD channel and also on the regular (SD) channel. That way i am sure that one of them will be recorded.