The Linux kernel patches could do the exact same thing, or some other malbehaviour. The root problems are in the processor, not the OS.
That is not a given. More than likely a part of the patch failed to take into account a architectural difference on the AMD CPUs, which is ironic since AMD64 is defined by AMD, not Intel.
MS rushed out a patch for their Intel compute farm customers, is the more likely issue.
Probably the bug in the code was not revealed on Intel is more likely. Or it was tested on AMD, but due to risk to large customers, MS decided their Intel customers with vast compute farms were more important in the immediate.
Not a conspiracy, but follows business logic.
Though one would hope us other paying customers will get a AMD clean fix soon.
...and not be force fed the bad fix in the interim.