None of this has to do with the Mach part of XNU. There are genuine bugs there (everyone hates the memory code for example) but again that is completely irrelevant here.
Really? I remember Bertrand Serlet or maybe it was Avie himself, taking pride in that.
How do you know Mach wasn’t the cause of some workaround in the 90s, and that 5 workarounds in a row later it becomes harder to resolve this issue in 2024?