This was definitely the "no arrow keys because we have a mouse" era of Apple. Everything we take for granted today was still in flux, and I can certainly imagine that even by the Macintosh 512k, just enough dust had settled that Jobs had reconsidered the idea of intentionally non-deterministic OS behavior.

True, after enough floppy swaps, your Mac probably was doing something like this. Hopefully removed the next time Disinfectant was run.