I don't know if there was an official announcement, but it's clear to me that NBA refs have decided or were told to start calling the game differently this season. There's definitely more contact being allowed on drives to the basket in general, to the point where absolutely blatant fouls are going uncalled. It's nice to not have so many "automatic fouls" anytime a guy takes it to the rim, but I've already seen more than a few games this season where a team has really been hurt by not getting obvious fouls called when they drive to the basket.
Mike