`builtin` command works differently in bash and ksh. In bash it executes the builtin and in ksh it enables a builtin of the name that is passed as argument. Fixing this issue requires changing behavior of `buitlin` command in ksh, but it can not be done to retain backward compatiblity.

Another way of fixing this is to detect whether ksh is used using $SHELL and not redirect to "builtin" in that case.

You are right, but I would prefer to leave this as a limitation rather then trying to workaround a solution for every possible shell. These scripts should have never been added at first place.

Current /usr/bin/cd:
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
#!/bin/sh
builtin cd "$@"
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

Proposed /usr/bin/cd (and the like in /usr/bin):
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
#!/bin/sh
[ -z "$KSH_VERSION" ] && builtin cd "$@" || cd "$@"
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

Please re-evaluate.

Your script works around this bug, but it assumes `builtin` keyword works same way in every other shell than ksh. `builtin` keyword is not defined by posix, so it's behavior may vary across shells, so this script may break again with other shells.