Validate template with openstack source requires real creds

Hello! Just want to ask about this case: I have template with openstack builder and when I run “validate” command I need to use real creds otherwise I have an error about failed auth.
Any opportunity do not use real creds during “validate”?
It does not work also when I tried to run it with “mocked” vars:

packer validate \
       -var 'ovh_test_account_username=mock_user' \
       -var 'ovh_test_account_password=mock_user' \
        <template_file>

Result:

Error: 1 error(s) occurred:

* Authentication failed

  on jenkins-agents.pkr.hcl line <line number>:
  (source code not available)

Simplified content of template:

packer {
  required_plugins {
    amazon = {
      version = ">= 1.1.1"
      source  = "github.com/hashicorp/amazon"
    }
    googlecompute = {
      version = ">= 1.1.1"
      source  = "github.com/hashicorp/googlecompute"
    }
    upcloud = {
      version = ">=v1.0.0"
      source  = "github.com/UpCloudLtd/upcloud"
    }
  }
}
source "openstack" "ovh-x86_64" {
    username = var.ovh_test_account_username
    password = var.ovh_test_account_password
    domain_name = "<domain>"
    identity_endpoint = "<url>"
    source_image_name = var.ovh_source_image_names["f37"]
    flavor = "<flavor>"
    region = "<reg>"
    tenant_id = "<id>"
    ssh_username = "<name>"
    networks = ["<net>"]
}
build {
name = "build_name"
source "openstack.ovh-x86_64" {
    name = "ovh-f37-x86_64"
    image_name = "image_name"
  }
}

Did you find a solution to this? I’m seeing the same issue with 1.9.1.