"Regardless, doesn't anybody at Apple use postgres?"
This problem occurs if you use anti-virus that delays file activities, and is 100% API consistent. Anyone saying "well it didn't do it before!" is being idiotic, similar to saying you don't need to check the return of malloc because it's usually going to succeed.
Regardless, doesn't anybody at Apple use postgres? Breaking Postgres should be hard to miss.
[1] https://pubs.opengroup.org/onlinepubs/009695399/functions/si...
[2] https://developer.apple.com/library/archive/documentation/Sy...