Last week -Backstage meddling has caught up “American Idol” favorite David Archuleta’s dad, who’s been banned from rehearsals, a person working for the TV talent contest said Friday.

Jeff Archuleta was told this week by producers that he can no longer join his 17-year-old son David as he prepares for the show, the person familiar with the matter told The Associated Press. The person wasn’t authorized to…