JIT engines (and compilers) often generate a familiar instruction patterns. Many JIT engines Target specific languages (like JS) and as result have "simpler" op

JIT engines (and compilers) often generate a familiar instruction patterns. Many JIT engines Target specific languages (like JS) and as result have "simpler" optimizers (less time to do this) and possibly more stable instruction patterns. So my money is on somebody fuzzing the required JS code.