A reference to a resource type must be followed by at least one attribute access, specifying the resource name.

[exzero16]

.\terraform-aws-cloud-modules\examples\spk_tgw_gwlb_asg_fgt_gwlb_igw\main.tf

terraform plan
╷
│ Error: Invalid reference
│
│ on main.tf line 88, in locals:
│ 88: existing_rt = lookup(var.existing_rts, "ngw_${az}", null),
│
│ A reference to a resource type must be followed by at least one attribute access, specifying the resource name.

terraform version
Terraform v1.14.6
on windows_amd64

• provider registry.terraform.io/hashicorp/archive v2.7.1
• provider registry.terraform.io/hashicorp/aws v6.34.0
• provider registry.terraform.io/hashicorp/null v3.2.4

Getting this error whenever I try to run plan or apply with the example terraform.

I can comment out that line and the code will run.