Can't set field names with Given users behat call When I run the following behat test:

Scenario: Logs in to the site
  Given users:
  | name     | pass        | mail                  | roles         | status | field_fir | field_la |
  | someuser | sompassword | someone@xenomedia.com | administrator | 1      | Some      | User     |
  Given I am on "/user"
  When I fill in "Username" with "someuser"
    And I fill in "Password" with "sompassword"
    And I press "Log in"
  Then I should see "Some User"
  Then I visit "user/logout"
  Then I should be on the homepage


I get the following error:

Given users:                                # Drupal\DrupalExtension\Context\DrupalContext::createUsers()
  | name     | pass        | mail                  | roles         | status | field_fir | field_la |
  | someuser | sompassword | someone@xenomedia.com | administrator | 1      | Some      | User     |
  Warning: explode() expects parameter 2 to be string, array given in /var/www/xmd8/vendor/drupal/drupal-extension/src/Drupal/DrupalExtension/Context/RawDrupalContext.php line 316


The weird thing is if I remove field_fir and change Then I should see "Some User" to Then I should see "User, it works.  For some strange reason it doesn't like field_fir. I verified that field_fir and field_la have exactly the same settings.
I didn't think this was the issue but I recently upgraded to PHP 7.  I downgraded to PHP 5.6 and the issue went away.  I created an issue on Drupal.org.

Turns out that I was using an older version of drupal-extension.  Upgraded to and the issue went away:

"drupal/drupal-extension": "^3.2",