Is there a timeout on how long Tablo waits to create thumbnails if a tuner is unavailable? I haven't paid a lot of attention to this, but have had a few programs for which thumbnails were not created. With my 4 tuner Tablo, I sometimes record as many as 3 programs simultaneously, and possibly watch live tv on the 4th tuner.
Does Tablo wait a certain length of time for a tuner to become available, and then give up? In the future, I'll pay closer attention and see if I can spot a pattern.