In order to correctly determine your watched or collected progress, all episodes need air dates. We use this date to know if the episode has actually aired or not. For currently airing shows, this ensures future episodes aren't counted. For shows that have ended, this helps so that unaired (for cancelled shows) or DVD only episodes aren't counted. You can add air dates on TVDB and Trakt.tv will automatically sync up that night. Your progress will start calculating correctly after Trakt.tv has the air dates.