What is the failed dependency during cryptography setup of systemd?

I'm somewhat sure now that noauto in /etc/fstab was not properly/fully honoured because it was not specified for /etc/crypttab as well:

https://www.freedesktop.org/software/systemd/man/crypttab.html#noauto

After adding it there too, the error has changed slightly:

Aug 22 22:27:07 example.org systemd[1]: dev-disk-by\x2duuid-7d39d2ed\x2df91f\x2d456e\x2daa31\x2d851cfe48de1b.device: Job dev-disk-by\x2duuid-7d39d2ed\x2df91f\x2d456e\x2daa31\x2d851cfe48de1b.device/start timed out.
Aug 22 22:27:07 example.org systemd[1]: Timed out waiting for device dev-disk-by\x2duuid-7d39d2ed\x2df91f\x2d456e\x2daa31\x2d851cfe48de1b.device.
Aug 22 22:27:07 example.org systemd[1]: Dependency failed for Cryptography Setup for mnt_luks_crypt.
Aug 22 22:27:07 example.org systemd[1]: systemd-cryptsetup@mnt_luks_crypt.service: Job systemd-cryptsetup@mnt_luks_crypt.service/start failed with result 'dependency'.
Aug 22 22:27:07 example.org systemd[1]: dev-disk-by\x2duuid-7d39d2ed\x2df91f\x2d456e\x2daa31\x2d851cfe48de1b.device: Job dev-disk-by\x2duuid-7d39d2ed\x2df91f\x2d456e\x2daa31\x2d851cfe48de1b.device/start failed with result 'timeout'.

The lines containing dev-mapper-mnt_luks_crypt.device are gone now. But there is still something happening and failing I don't understand and systemd lacks to log details for.