The last post in this thread ( Really Mad - Failed to Record AGAIN ) tells users how to request the beta firmware if you are struggling with the lost recordings issue. I requested the beta and for the last two days, my shows have been recording flawlessly, including a very busy Wednesday night schedule. It did not bring back my lost recordings, though (not sure if it was supposed to) but I am just relieved I don’t have to keep checking to make sure all my shows are recording anymore.
As a side note, I have noticed that since upgrading the firmware, that the delete function is much more responsive than it used to be. That was a pleasant surprise.
Note that when I was having this problem, I found that if the show was going to fail, the thumbnail does not appear in the Recordings section even though it is showing in the guide list that it is recording (orange scheduled icon in the corner and channel number flashing red). If I saw the thumbnail was missing at the beginning of a show, I stopped the recording and started it again and it would record from that point on (with the thumbnail showing up right away in the Recordings section). If I caught it in the middle of a show, I did not stop the recording because that would only record from that point on. Instead, I went to watch live and rewound all the way back to the beginning of the episode. Unfortunately, there were several shows that I was not home to babysit and those shows just got lost.