A gas turbine engine support system includes a vane arc segment, a vane support arc segment piece configured to engage the vane arc segment, and a seal disposed radially between the vane arc segment and the vane support arc segment piece. The seal includes first and second seal sections. The first seal section has a floor wall and first and second side walls that project from the floor wall. The first and second side walls converge to define a disjointed corner. The second seal section nests with the first seal section and seals the disjointed corner.