At one point, for many years, it would just sometimes fail to `exec()` a process. This would manifest as a random failure on our build farm about once/twice a month. (This would manifest as "/bin/sh: fail to exec binary file" because the error type from the kernel would have the libc fall back to trying to run the binary as a script, as normal for a Unix, but it isn't a script)
This is likely stemming from their exiting the server business years ago, and focusing on consumer appeal more than robustness (see various terrible releases, security- and stability-wise).
(I'll grant that macOS has many features that would make it a great server OS, but it's just not polished enough in that direction)