Comment 1 for bug 1875577

I don't know exactly why this manifests as a dependency loop, but your /etc/crypttab is certainly wrong; the first column of /etc/crypttab is the target device name, and you cannot have two separate source encrypted devices map to the same decrypted device name.

If you give the two devices separate names (e.g. swap1, swap2), does this work for you?

If not this should probably be reassigned to systemd, since those systemd units are created by a systemd generator and not by the cryptsetup package.