ibm_is_ssh_key changes not being reflected

[jandroav]

Hello.
I am using the code from terraform-single and we saw that newly added ssh keys are not being used by existing ibm_is_instance resources. i.e:

variable "ssh_public_keys" {
  type = map(string)
  default = {
    user1   = "SAMPLE_SSH_PUBLIC_KEY1",
    user2   = "SAMPLE_SSH_PUBLIC_KEY2",
    user3   = "SAMPLE_SSH_PUBLIC_KEY3",
    user4 = "SAMPLE_SSH_PUBLIC_KEY4"
  }
}

resource "ibm_is_ssh_key" "sshkey" {
  for_each   = var.ssh_public_keys
  name       = each.key
  public_key = each.value
}

resource "ibm_is_instance" "testacc_vsi" {
  name = "db2z1"
  #image   = local.image.id
  image   = "r038-043c2fc5-0baf-4825-916b-63f4755acc30"
  profile = local.profile

  primary_network_interface {
    subnet          = ibm_is_subnet.testacc_subnet.id
    security_groups = [ibm_is_security_group.testacc_security_group.id]
  }

  vpc  = ibm_is_vpc.testacc_vpc.id
  zone = "${var.region}-${var.zone}"
  keys = values(ibm_is_ssh_key.sshkey)[*].id
}

If an ibm_is_instance is created and then we add a new ssh key to the variable above, we can see the key created in the IBM Cloud UI but not being used by the virtual server. We need to recreate the instance every time we add a new public key.

Is there any workaround to avoid destroying the existing instances?