openstack overcloud ffwd-upgrade run --yes generates inventory with wrong ansible_ssh_user:

(undercloud) [stack@undercloud-0 ~]$ openstack overcloud ffwd-upgrade run --yes
Warning! The TripleO Fast Forward Upgrade workflow is currently considered under development. In particular invocations of the ffwd-upgrade cli should be initially limited to development/test environments. Once and if you decide to use ffwd-upgrade in production, ensure you are adequately prepared with valid backup of your current deployment state.
Continuing fast forward upgrade
Started Mistral Workflow tripleo.package_update.v1.update_nodes. Execution ID: b00c6b64-b809-4556-b0ec-97f1d9b60a79
Waiting for messages on queue 'ffwdupgrade' with no timeout.
[u'Using /tmp/ansible-mistral-actionAS5fdE/ansible.cfg as config file',
 u' [WARNING]: Skipping unexpected key (hostvars) in group (_meta), only "vars",',
 u'"children" and "hosts" are valid',
 u'',
 u'PLAY [overcloud] ***************************************************************',
 u'',
 u'TASK [Gathering Facts] *********************************************************',
 u'fatal: [192.168.24.15]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: Could not create directory \'/home/mistral/.ssh\'.\\r\\nWarning: Permanently added \'192.168.24.15\' (ECDSA) to the list of known hosts.\\r\\nPermission denied (publickey,gssapi-keyex,gssapi-with-mic).\\r\\n", "unreachable": true}',
 u'fatal: [192.168.24.13]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: Could not create directory \'/home/mistral/.ssh\'.\\r\\nWarning: Permanently added \'192.168.24.13\' (ECDSA) to the list of known hosts.\\r\\nPermission denied (publickey,gssapi-keyex,gssapi-with-mic).\\r\\n", "unreachable": true}',
 u'fatal: [192.168.24.17]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: Could not create directory \'/home/mistral/.ssh\'.\\r\\nWarning: Permanently added \'192.168.24.17\' (ECDSA) to the list of known hosts.\\r\\nPermission denied (publickey,gssapi-keyex,gssapi-with-mic).\\r\\n", "unreachable": true}',
 u'fatal: [192.168.24.19]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: Could not create directory \'/home/mistral/.ssh\'.\\r\\nWarning: Permanently added \'192.168.24.19\' (ECDSA) to the list of known hosts.\\r\\nPermission denied (publickey,gssapi-keyex,gssapi-with-mic).\\r\\n", "unreachable": true}',
 u'fatal: [192.168.24.12]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: Could not create directory \'/home/mistral/.ssh\'.\\r\\nWarning: Permanently added \'192.168.24.12\' (ECDSA) to the list of known hosts.\\r\\nPermission denied (publickey,gssapi-keyex,gssapi-with-mic).\\r\\n", "unreachable": true}',
 u'fatal: [192.168.24.10]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: Could not create directory \'/home/mistral/.ssh\'.\\r\\nWarning: Permanently added \'192.168.24.10\' (ECDSA) to the list of known hosts.\\r\\nPermission denied (publickey,gssapi-keyex,gssapi-with-mic).\\r\\n", "unreachable": true}',
 u'fatal: [192.168.24.18]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: Could not create directory \'/home/mistral/.ssh\'.\\r\\nWarning: Permanently added \'192.168.24.18\' (ECDSA) to the list of known hosts.\\r\\nPermission denied (publickey,gssapi-keyex,gssapi-with-mic).\\r\\n", "unreachable": true}',
 u'fatal: [192.168.24.23]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: Could not create directory \'/home/mistral/.ssh\'.\\r\\nWarning: Permanently added \'192.168.24.23\' (ECDSA) to the list of known hosts.\\r\\nPermission denied (publickey,gssapi-keyex,gssapi-with-mic).\\r\\n", "unreachable": true}',
 u'',
 u'PLAY RECAP *********************************************************************',
 u'192.168.24.10 : ok=0 changed=0 unreachable=1 failed=0 ',
 u'192.168.24.12 : ok=0 changed=0 unreachable=1 failed=0 ',
 u'192.168.24.13 : ok=0 changed=0 unreachable=1 failed=0 ',
 u'192.168.24.15 : ok=0 changed=0 unreachable=1 failed=0 ',
 u'192.168.24.17 : ok=0 changed=0 unreachable=1 failed=0 ',
 u'192.168.24.18 : ok=0 changed=0 unreachable=1 failed=0 ',
 u'192.168.24.19 : ok=0 changed=0 unreachable=1 failed=0 ',
 u'192.168.24.23 : ok=0 changed=0 unreachable=1 failed=0 ',

[root@undercloud-0 stack]# grep ansible_ssh_user /tmp/ansible-mistral-actionAS5fdE/inventory.yaml
    ansible_ssh_user: overcloud
    ansible_ssh_user: overcloud
    ansible_ssh_user: overcloud
  vars: {ansible_ssh_user: overcloud}