Fans of the CBS procedural drama Blue Bloods have pointed out a major blunder in season 7 while re-watching the show to prepare for the upcoming release of season 13 in October. One viewer noticed that the T-mark used for accuracy was visible on the floor during a scene in which it should not have been, exposing an error in production. The series follows the lives of the Reagan family and their work in law enforcement. Despite the blunder, fans are still eagerly anticipating the return of the show next month.