LEC is major static tool to qualify the RTL versus Netlist equivalence. The usage does not just limit in dealing with the equivalence check but also in generating the patch for ECO fixes in the netlist. LEC has its own vulnerability in dealing with constant propagation modelling. It has been experienced as a showstopper silicon bug that took a huge effort in RCA and fix. The paper demonstrates LEC escapee and recommendation to cover up the gap to eliminate such a showstopper silicon bug.