Warning: Illegal string offset 'field' in EntityReference_SelectionHandler_Generic_user->entityFieldQueryAlter()

every query contains a #conjunction

  /**
   * Constructs a DataBaseCondition object.
   *
   * @param string $conjunction
   *   The operator to use to combine conditions: 'AND' or 'OR'.
   */
  public function __construct($conjunction) {
    $this->conditions['#conjunction'] = $conjunction;
  }