clear the fb variance when resetting tfcn as well
clear the fb variance when resetting tfcn as well

ospray/OSPRay,ospray/OSPRay,ospray/OSPRay,wilsonCernWq/ospray,ospray/OSPRay,MengjiaoH/ospray,MengjiaoH/ospray,wilsonCernWq/ospray,MengjiaoH/ospray,wilsonCernWq/ospray,MengjiaoH/ospray,MengjiaoH/ospray