Three weeks before a Democratic Party primary in which East Hampton Town Councilman Jeff Bragman will challenge Supervisor Peter Van Scoyoc, a furious argument broke out among the town board, with Mr. Bragman seizing on a letter from the town's board of ethics that criticized town board members for having taken guests to a May 7 event at the Clubhouse in Wainscott honoring pandemic frontline workers and food pantry staff and featuring a performance by the Rock and Roll Hall of Famer Jon Bon Jovi.