Misleading error message when trying to change project's domain

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We are running a Mitaka environment. When browsing ask.openstack.org there was a question about changing a project's domain and I wanted to test if that works. According to [1] it's not designed to be changed, but there is still the option in openstackclient:
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(openstack) project set -h
usage: project set [-h] [--name <name>] [--domain <domain>]
                   [--description <description>] [--enable | --disable]
                   [--property <key=value>]
                   <project>

Set project properties

positional arguments:
  <project> Project to modify (name or ID)

optional arguments:
  -h, --help show this help message and exit
  --name <name> Set project name
  --domain <domain> Domain owning <project> (name or ID)
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Executing the command with a valid project ID leads to an error, saying there is no such project:
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control1:~ # openstack domain list
+----------------------------------+---------+---------+-------------------+
| ID | Name | Enabled | Description |
+----------------------------------+---------+---------+-------------------+
| 696819fc8d8d40129ca3a7b54145ba9e | heat | True | Stack projects ...|
| d17c72d57ef344da922500b4f69de4b2 | users | True | User domain |
| default | Default | True | Owns users and ...|
+----------------------------------+---------+---------+-------------------+

control1:~ # openstack project list
+----------------------------------+-----------+
| ID | Name |
+----------------------------------+-----------+
| 1d8581b15e714e59a7ab15c598809b11 | SES |
| 2e2408fba09844809e6b8c65529cb3f8 | DEMO |
| 4654ccbd038b45c4a92f18c0f0999bbf | SERVICE |
| 67ba6231930c4e13b2b1c6ba5972921f | PLA |
| 90c403f317ee47feb0dad58461e76fb1 | ADMIN |
+----------------------------------+-----------+

control1:~ # openstack project show 67ba6231930c4e13b2b1c6ba5972921f
+-------------+-------------------------------------+
| Field | Value |
+-------------+-------------------------------------+
| description | |
| domain_id | d17c72d57ef344da922500b4f69de4b2 |
| enabled | True |
| id | 67ba6231930c4e13b2b1c6ba5972921f |
| is_domain | False |
| name | PLA |
| parent_id | d17c72d57ef344da922500b4f69de4b2 |
+-------------+-------------------------------------+

control1:~ # openstack project set --domain default 67ba6231930c4e13b2b1c6ba5972921f
No project with a name or ID of '67ba6231930c4e13b2b1c6ba5972921f' exists.
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Obviously, that's not true. If it's not supposed to be changed, I would expect a correct error message or the option should be disabled.

Please let me know if I there's more information required.

[1] https://bugs.launchpad.net/keystone/+bug/1418384