--- Comment #6 from Stefan Hundhammer firstname.lastname@example.org --- Notice that the tools using that directory check /run/cryptsetup-keys.d as well as /etc/cryptsetup-keys.d . /run is a tmpfs created and mounted by the kernel (or systemd?) very similar to /proc and /sys.
You might want to check there as well.
I don't have a directory cryptsetup-keys.d in either location, not in /etc and not in /run.