Note that even if fixed, it will probably still fail the actual deletion of the secret if the user defined in the keystone_authtoken section lacks permisisons in Barbican to delete secrets created by another user (which is the case in the default setup of Barbican API policies and ACLs), but at least the error will be much more readable and proper (and it will actually work if barbican api policies are properly adjusted, same as when admin deletes encrypted volume created by another user in another project).
Note that even if fixed, it will probably still fail the actual deletion of the secret if the user defined in the keystone_authtoken section lacks permisisons in Barbican to delete secrets created by another user (which is the case in the default setup of Barbican API policies and ACLs), but at least the error will be much more readable and proper (and it will actually work if barbican api policies are properly adjusted, same as when admin deletes encrypted volume created by another user in another project).