I don't think that is a fair statement. Often writers of emulators have to take low level shortcuts because the alternative is emulating the physical hardware i

I don't think that is a fair statement. Often writers of emulators have to take low level shortcuts because the alternative is emulating the physical hardware in software - which is extremely slow. A "bug" implies that a behavior is unintended or undesired where as sometimes these kinds of emulator facets are deliberately implemented for the sake of simplifying the emulator design or just being about to use modern hardware to offload some of the processing (like a hypervisor would) rather than having to emulate every single transistor in a now defunct chipset.