I've had similar problems with mine...

Few minute or few minutes of a show not getting recorded, so I only get a partial (you said you missed 25 mins of a show - that's way more than what I'm seeing). Also, the other day, 2 shows were missed completely, and when I looked in recording history and selected the show, it rebooted. After rebooting, recording history showed that the shows were not recorded due to power being disconnected, which it wasn't...

I've searched TiVo Community for these issues, and people have thought that they were due to problems with the signal from the satellite, which I think is unlikely.

- Jon