Today, I noticed another problem with the Series3. About half of the recordings were "partial" with duration of 0:00. It turns out that only one of the two CableCards were activated. So all of the recordings from digital cable channels, on that tuner, were failing.
The TiVo should have been able to identify this problem after setup. The TiVo could have process where it tunes to every channel on both tuners. Then it could verify that the content on both tuners is the same.