hook_entity_access doesn't fire on add operation

I just encountered this problem too. After some debugging, I discovered that the issue was due to having the "bypass ECK entity access" permission. When you have this permission, the hook_entity_access is never called.

As per /src/EckEntityAccessControlHandler.php#L52

  public function access(EntityInterface $entity, $operation, AccountInterface $account = NULL, $return_as_object = FALSE) {
    if ($this->canBypassAccessCheck($account)) {
      return $this->getBypassAccessResult($return_as_object);
    }
    else {
      return parent::access($entity, $operation, $account, $return_as_object);
    }
  }