Check the History screen as previously suggested. Also, so I understand clearly, had your Tivo been recording this specific season of shows earlier this year, but has failed to record the last 2? Or had a new season of this show just recently started and the Tivo had missed the first 2 shows of the season? Perhaps the last two broadcast showings were re-runs? It's not uncommon for networks to do re-runs of shows leading into the Holidays.
While season passes work generally very well, there can be some instances where the show title changes slightly, or the guide data provided by Tribune Media Services is changed for a show which causes the season pass to break.