From @zoffixznet

Trying to make RT recognize OP's text as... text... They wrote​:

$*SPEC.splitpath("foo/bar/baz").perl

("", "foo/bar/", "baz")

$*SPEC.splitpath("foo/bar/\x[308]baz").perl

("", "foo/", "bar/Ìbaz")

The latter pathname, if actually used for I/O, unsurprisingly functions
as a three-element pathname, just like the first one, based on the
octets of its UTF-8 representation. splitpath fails to recognise the
second directory separator, because it's working in the grapheme world.
It needs to use the octet view. There are obvious security implications
in failing to correctly parse pathnames.

-zefram