A Secret Service agent suspected of leaking details about Vice President JD Vance’s travel has been placed on administrative leave pending an internal investigation. The unidentified agent is believed to have been a source for an MS Now story published last week that claimed Vance’s protective detail was frustrated with the second family’s habit of making last-minute travel arrangements and special requests. “A member of the Vice Presidential Protective Division is the subject of an administrative investigation, and potential criminal inquiry, involving allegations of compromising operational and information security,” a Secret Service spokesperson told The Post Thiursday.