Notice: Uninitialized string offset: 0 in Drupal\Core\Render\Element::property()

The fix in #2905907: Notice: Uninitialized string offset: 0 in Drupal\Core\Render\Element::property() (line 27 of /var/www/html/core/lib/Drupal/Core/Render/Element.php) was only applied to validateFormRecursive(). I am still getting that error, but now it is on the submit function which uses similar code to what was replaced in the validate function.

Error:

Notice: Uninitialized string offset: 0 in Drupal\Core\Render\Element::property() (line 27 of core/lib/Drupal/Core/Render/Element.php)

#0 core/includes/bootstrap.inc(584): _drupal_error_handler_real()
#1 core/lib/Drupal/Core/Render/Element.php(27): _drupal_error_handler()
#2 modules/contrib/webform/src/WebformSubmissionConditionsValidator.php(265): Drupal\Core\Render\Element::property('')
#3 modules/contrib/webform/src/WebformSubmissionConditionsValidator.php(245): Drupal\webform\WebformSubmissionConditionsValidator->submitFormRecursive(Array, Object(Drupal\webform\Entity\WebformSubmission), Array)

This is addressed by making the same change in #2905907: Notice: Uninitialized string offset: 0 in Drupal\Core\Render\Element::property() (line 27 of /var/www/html/core/lib/Drupal/Core/Render/Element.php) to submitFormRecursive()

if (Element::property($key) || !is_array($element)) {
  continue;
}

to

if (Element::child($key) || !is_array($element)) {
        continue;
      }

patch forthcoming -