If person didn't had quest at time of a kill - we can't add item to him. To know that he had quest at that time - we need to check it from backup. That's why I'm asking time. To be sure that he had quest at time of a kill.
Every bug is different and differently affect gameplay or don't affect at all and all of this are subjectively, so people will start argue with us about how much bug affecting game just to get better reward...