The South Orange-Maplewood School District has placed an administrator on leave for the second time since November. Frank Sanchez, principal of Columbia High School in Maplewood, was put on leave on Tuesday morning for reasons district officials did not explain. In a letter Tuesday to the Columbia High School community, acting Superintendent Kevin Gilbert said that “no one in the district is at liberty to share any details “ about Sanchez’s absence. He said Ann Bodnar, assistant superintendent of Curriculum and Instruction, would serve as acting principal until the district appointed a replace…