I had a butterfly in CLX12 centered at 92 which expired yesterday at 92.04. That makes the middle call ITM and the put OTM by 0.04. It is my understanding that traders can enter contrary instructions up to 2 hours after expiration (i.e. 4:30pm Eastern). I noted CLX12 trading crossed the 92 strike a couple dozen times and traded as low as 91.83 during that two hours, yet the put was not exercised. Why would a trader abandon an option that is worth as much as $170? Inexperience? Inattention? Am I missing something? How common is this?