User creation fails due to missing`mailman` group

The following error happens now on gnumailman but further inspection will show that:

1. this group exists already
2. these users exist already
3. these users are IN the group...

gnumailman.nyc1.psf.io:
----------
          ID: maxking-user
    Function: user.present
        Name: maxking
      Result: False
     Comment: The following requisites were not found:
                                 require:
                                     group: mailman
     Started: 18:26:05.534031
    Duration: 0.01 ms
     Changes:
----------
          ID: maxking-ssh_dir
    Function: file.directory
        Name: /home/psf-users/maxking/.ssh
      Result: False
     Comment: One or more requisite failed: users.maxking-user
     Started: 18:26:05.535490
    Duration: 0.01 ms
     Changes:
----------
          ID: maxking-ssh_key
    Function: file.managed
        Name: /home/psf-users/maxking/.ssh/authorized_keys
      Result: False
     Comment: One or more requisite failed: users.maxking-user
     Started: 18:26:05.536482
    Duration: 0.006 ms
     Changes:
----------
          ID: msapiro-user
    Function: user.present
        Name: msapiro
      Result: False
     Comment: The following requisites were not found:
                                 require:
                                     group: mailman
     Started: 18:26:05.541196
    Duration: 0.008 ms
     Changes:
----------
          ID: msapiro-ssh_dir
    Function: file.directory
        Name: /home/psf-users/msapiro/.ssh
      Result: False
     Comment: One or more requisite failed: users.msapiro-user
     Started: 18:26:05.542288
    Duration: 0.006 ms
     Changes:
----------
          ID: msapiro-ssh_key
    Function: file.managed
        Name: /home/psf-users/msapiro/.ssh/authorized_keys
      Result: False
     Comment: One or more requisite failed: users.msapiro-user
     Started: 18:26:05.543097
    Duration: 0.005 ms
     Changes:

Summary for gnumailman.nyc1.psf.io
--------------
Succeeded: 143 (changed=6)
Failed:      6

Start by reproducing the failure on gnumailman.nyc1.psf.io and inspect the configuration defining the mailman group and the affected users. Trace why the user.present requisites cannot find group: mailman, then verify that the users and their dependent SSH directory and key states complete successfully.