These are probably Series Record timers:
1. The next episode has yet to appear in the EPG, and therefore the unit cannot find the next occurrence. If the Series is still current, but taking a 'break' it will update when it re-appears in the EPG.
2. The Series has ended. In this case the timer will stay in the list for 13 weeks after the last episode, and then auto delete. If the user is aware that the Series has ended then they can delete it themselves.
