One enduring complaint about PVRs is that networks sometimes schedule a show just over the half hour mark, for instance ending at 8:31 or starting at 9:29. It's either an effort to transfer viewers to another show or a conspiracy to punish PVR users for skipping commercials.
Either way, it looks like TiVo's doing something about it. A knowledge base article describes a new feature called "Overlap Protection" that, when enabled, will keep a show ending at 8:31 from preventing an 8:30 recording. When an overlap occurs, the TiVo will give preference to the show with a higher priority in the Season Pass manager.
This feature is reportedly part of the 7.2.1 software currently being distributed to Series 2 TiVos.