Out of college I interviewed at a place that makes flight simulators, not at the scale of Boeing likely but I’d imagine at the same level of ‘best practices’.

Out of college I interviewed at a place that makes flight simulators, not at the scale of Boeing likely but I’d imagine at the same level of ‘best practices’. I was surprised to learn that at least at that place, the actual aircraft software was running in the simulator, and that external sensor inputs to the software were being mocked out. It was surprising to me because I had never thought of a simulator as simulating the aircraft itself, but rather only the experience of flying it. So from this, I don’t think it the case that a simulator is having trouble recreating flight characteristics or reimplementing a ‘bug’ or other behavior because my guess is they are not reimplementing much/anything on the software level. Though your point about bugs only surfacing after many hours of continuous operation could theoretically still occur without further controls, and of course it is hard to make a mock full-fidelity, especially so in the context of a full suite of analog flight sensors/actuators.