Can't handle multiple IP whitelist resources

I have multiple IP whitelist resources set up for the same project, but they seem to behave inconsistently.

Behaviour: Initial terraform apply succeeds; subsequent apply's seem to get increasingly confused about what the whitelists are. It seems that it wasn't able to correctly link the resources to their representation from Atlas.

resource "mongodbatlas_ip_whitelist" "server" {
  group      = "${mongodbatlas_project.project.id}"
  cidr_block = "${aws_instance.server.public_ip}/32"
}

resource "mongodbatlas_ip_whitelist" "subnet_a" {
  group      = "${mongodbatlas_project.project.id}"
  cidr_block = "${aws_subnet.subnet_a.cidr_block}"
}

resource "mongodbatlas_ip_whitelist" "subnet_b" {
  group      = "${mongodbatlas_project.project.id}"
  cidr_block = "${aws_subnet.subnet_b.cidr_block}"
}

Terraform apply run 1:

$ terraform apply

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:

  + mongodbatlas_ip_whitelist.server
      id:         <computed>
      cidr_block: "13.x.x.x/32"
      comment:    "Access for the dedicated server"
      group:      "5aba24a197019902d2e2698c"
      ip_address: <computed>

  + mongodbatlas_ip_whitelist.subnet_a
      id:         <computed>
      cidr_block: "10.1.100.0/24"
      comment:    "Access from Subnet A"
      group:      "5aba24a197019902d2e2698c"
      ip_address: <computed>

  + mongodbatlas_ip_whitelist.subnet_b
      id:         <computed>
      cidr_block: "10.1.101.0/24"
      comment:    "Access from Subnet B"
      group:      "5aba24a197019902d2e2698c"
      ip_address: <computed>

Plan: 3 to add, 0 to change, 0 to destroy.

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes

mongodbatlas_ip_whitelist.subnet_b: Creating...
  cidr_block: "" => "10.1.101.0/24"
  comment:    "" => "Access from Subnet B"
  group:      "" => "5aba24a197019902d2e2698c"
  ip_address: "" => "<computed>"
mongodbatlas_ip_whitelist.subnet_a: Creating...
  cidr_block: "" => "10.1.100.0/24"
  comment:    "" => "Access from Subnet A"
  group:      "" => "5aba24a197019902d2e2698c"
  ip_address: "" => "<computed>"
mongodbatlas_ip_whitelist.server: Creating...
  cidr_block: "" => "13.x.x.x/32"
  comment:    "" => "Access for the dedicated server"
  group:      "" => "5aba24a197019902d2e2698c"
  ip_address: "" => "<computed>"
mongodbatlas_ip_whitelist.server: Creation complete after 3s (ID: 13.211.169.74/32)
mongodbatlas_ip_whitelist.subnet_a: Creation complete after 3s (ID: 10.1.100.0/24)
mongodbatlas_ip_whitelist.subnet_b: Creation complete after 3s (ID: 10.1.100.0/24)

Apply complete! Resources: 3 added, 0 changed, 0 destroyed.

Terraform apply run 2 (no changes to templates):

$ terraform apply

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
-/+ destroy and then create replacement

Terraform will perform the following actions:

-/+ mongodbatlas_ip_whitelist.subnet_b (new resource required)
      id:         "10.1.100.0/24" => <computed> (forces new resource)
      cidr_block: "10.1.100.0/24" => "10.1.101.0/24" (forces new resource)
      comment:    "Access from Subnet A" => "Access from Subnet B"
      group:      "5aba24a197019902d2e2698c" => "5aba24a197019902d2e2698c"
      ip_address: "" => <computed>

Plan: 1 to add, 0 to change, 1 to destroy.

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes

mongodbatlas_ip_whitelist.subnet_b: Destroying... (ID: 10.1.100.0/24)
mongodbatlas_ip_whitelist.subnet_b: Destruction complete after 2s
mongodbatlas_ip_whitelist.subnet_b: Creating...
  cidr_block: "" => "10.1.101.0/24"
  comment:    "" => "Access from Subnet B"
  group:      "" => "5aba24a197019902d2e2698c"
  ip_address: "" => "<computed>"
mongodbatlas_ip_whitelist.subnet_b: Creation complete after 3s (ID: 13.211.169.74/32)

Apply complete! Resources: 1 added, 0 changed, 1 destroyed.

Terraform apply run 3 (still no changes to templates):

$ terraform apply

Error: Error refreshing state: 1 error(s) occurred:

* mongodbatlas_ip_whitelist.subnet_a: 1 error(s) occurred:

* mongodbatlas_ip_whitelist.subnet_a: mongodbatlas_ip_whitelist.subnet_a: Error reading MongoDB Project IP Whitelist 10.1.100.0/24: MongoDB Atlas: 404 IP Address 10.1.100.0/24 not on Atlas whitelist for group 5aba24a197019902d2e2698c.

akshaykarle / terraform-provider-mongodbatlas

Can't handle multiple IP whitelist resources #16