Cannot use an existing SSL policy

[Vermyndax]

TL;DR

I can't get this module to locate an existing SSL policy defined by Terraform.

Expected behavior

I have a Terraform resource that is creating a security policy to meet compliance requirements. I should be able to use this SSL policy with this module.

Observed behavior

This module seems to forcibly look for an SSL policy at a different URL, and therefore fails. I have tried referencing the resource URL with .id, .self_link, and .name. None of them work. The same error is returned:

Error: Error setting Backend Service security policy: googleapi: Error 400: Invalid value for field 'resource': '***  "securityPolicy": "projects/(redacted)/global/securityPolicies/minimum-tls"***'. The given security policy does not exist., invalid

The policy does exist.

Terraform Configuration

resource "google_compute_ssl_policy" "minimum_tls" {
  min_tls_version = "TLS_1_2"
  name            = "minimum-tls"
  profile         = "MODERN"
  project         = var.account_id
}

module "sparkpost_lb_https" {
  source  = "terraform-google-modules/lb-http/google//modules/serverless_negs"
  version = "~> 12.0"

  count   = var.environment == "develop" ? 1 : 0 # TODO: Develop only for now
  name    = "sparkpost-lb-${var.environment}"
  project = var.account_id

  ssl = true
  managed_ssl_certificate_domains = [
    var.sparkpost_ssl_domain
  ]
  https_redirect = false

  load_balancing_scheme = "EXTERNAL_MANAGED"

  backends = {
    default = {
      description = "Sparkpost click tracking backend"
      groups = [
        {
          group = google_compute_global_network_endpoint_group.sparkpost_neg[0].id
        }
      ]

      enable_cdn = false

      iap_config = {
        enable = false
      }

      log_config = {
        enable      = true
        sample_rate = 1.0
      }

      security_policy = google_compute_ssl_policy.minimum_tls.self_link
    }
  }
}

### Terraform Version

```sh
1.10.2

Additional information

I tried to force the issue by specifically setting security_policy as such:

security_policy = "projects/${var.account_id}/global/sslPolicies/minimum-tls"

...but I still got the same error, which indicated it was looking for the resource in a completely different area of GCP as above. I am able to select minimum-tis in the console for the frontend configuration after the load balancer is deployed.