I don’t know much about CPU and memory back then, but did they not have some kind of memory access debugging mode where it would match every access against the alloc map, understanding that it could be very slow, but would find some of this kind of bug? Come to think of it, do we even have that today?
There was such a tool, called Purify.
https://web.stanford.edu/class/cs343/resources/purify.pdf