http://espn.go.com/college-football/story/_/id/12395698/texas-defensive-coordinator-john-chavis-sues-lsu-buyout
Need one of the lawyers to answer this. Seems cut and dry, but then, that's usually when it's the most murky.
NCAA recruiting violation? He was either no longer an LSU coach in January, or he was illegally recruiting for TAMU. http://www.nola.com/lsu/index.ssf/2015/03/former_lsu_d-coordinator_john.html