A leak from inside the Boy Scouts of America last month about discussions on possibly ending the group’s national ban on gay members changed the debate itself by creating an impression that change was imminent, according to scouting officials and taped comments from a meeting of scouting’s executive board obtained by The New York Times. Those apparently false expectations were dashed days later when the board, under intense scrutiny it had never intended, deferred action. The proposed shift in policy has been portrayed in news accounts mostly as a kind of trial balloon, floated to gauge sentiment about where scouting might go on a hugely divisive question. But the proposal, though seriously in consideration, was not supposed to become public at this moment, Scouts officials confirmed. The plan for the meeting this week was a quiet discussion behind closed doors, they said, free from the outside pressures that have buffeted scouting, especially since summer, when the organization reaffirmed its ban on gay scouts and leaders after a two-year review.