I find it difficult to imagine how a change like this (sending a SIGKILL to the process instead of SIGSEGV on a page fault) can be done in the final release and not in one of the EA releases or betas. It is clearly a breaking change with no easy workaround (since SIGKILL cannot be caught), for a behaviour which is well defined by POSIX.

Even if you momentarily ignore the reasons why someone thought this could be a good idea, why not do it in one of the pre-releases or betas??? Doesn’t look like the kind of thing you’d want to do in a last minute change.

The real problem in my opinion is the fact that you cannot go back after a macOS upgrade. So if something like this happens, you literally have no option but waiting for Apple to release a fix, if they want to do it at all.