So I have product lifetime service for my TiVo Premiere and have had few complaints (although I can't for the life of me understand why both tuners end up on the same channel more often than not, but that's another story).
Anyway, last night I was checking the To Do list and noticed that my Sunday night shows (Copper, The Killing, and Falling Skies) next weekend (on the 14th) weren't going to be recorded. I thought, WTF? So I called up the "Live Guide" on the TiVo for each channel involved (BBC America, AMC and Syfy, respectively) and jumped forward through to the 14th, only to discover, for each of them, that there's a gap in the data from about 5 pm Sunday the 14th to 5 pm Monday the 15th. And it turns out it's not just those channels involved either (I randomly checked a couple more channels). What provoked my curiosity in the first place was wondering whether we were going to get a new Walking Dead episode next Sunday night, BTW.
For now I've set the Tivo, VCR-like, to record by time and channel, but I'm going to monitor it and see if the problem corrects itself. I'd be curious to find out if anyone else's TiVo is doing this.