Program seems to record but does not.

I have a program setup to record. It shows up in the to do list. The indicator light on the front panel of the TiVo lights up indicating that the program is being recorded. When I look in the Now Playing list the program is nowhere to be seen! This has only recently begun to happen. There are no conflicts that I can see and it is happening on two different TiVo units. One is a Premiere and the other is a HD Series 3. Has anyone else seen this or can someone tell me why this is happening??