Since hardware bugs are independent from software, there are two possibilities: either the way they use the hardware never exposed the problem in the first place or they ran into the problem, got their hardware guys to analyse it and implemented a workaround. In any case, I have no specific knowledge of what Apple have (or haven't) done.
any chance some Linux guys came across the issue? Or maybe it also affects the PC cards? If not it would narrow it down to the Mac hardware.