not refreshing state for opentelekomcloud_vbs_backup_policy_v2

[otc-fabo]

When creating a EVS disk using opentelekomcloud_blockstorage_volume_v2 with metadata (for KMS encryption) and attaching this disk to an VBS Backup policy using opentelekomcloud_vbs_backup_policy_v2 after the second terraform apply, the disk is removed from the VBS policy. This is due to the fact, the OTC sets a metadata parameter "policy" with the ID of the VBS-Policy, the disk is attached to. Terraform does not have this parameter in his resource, and therefore removes it with the second apply.
opentelekomcloud_vbs_backup_policy_v2 is not recognizing this because it seems it does not refresh its state.
The problem does not occur when using: opentelekomcloud_evs_volume_v3 because it does not use metadata

Terraform Version

terraform version
Terraform v0.12.28

• provider.openstack v1.29.0
• provider.opentelekomcloud v1.18.1

Affected Resource(s)

opentelekomcloud_vbs_backup_policy_v2
opentelekomcloud_blockstorage_volume_v2

Terraform Configuration Files

resource "opentelekomcloud_blockstorage_volume_v2" "volume" {
  count             = var.disk_size_gb > 0 ? var.computecount : 0
  availability_zone = data.openstack_compute_availability_zones_v2.available.names[count.index]
  name              = "${var.name}0${count.index + 1}-datadisk"
  size              = var.disk_size_gb
  tags              = merge(
    local.common_tags,
    {
      environment = var.environment
      generator   = "terraform"
      role        = var.role
    },
  )
  metadata = {
    __system__encrypted = "1"
    __system__cmkid     = var.kms_id
    attached_mode       = "rw"
    readonly            = "False"
  }
}

Debug Output

as visible on the screenshot, on the second apply, the 'metadata: policy' is removed. Therefore the Disk is not attached to the vbs policy anymore

Expected Behavior

disk should be still attached to the vbs policy

Actual Behavior

disk is removed from vbs policy

Steps to Reproduce

1. create a evs disk with metadata
2. attach disk to a vbs policy
3. rerun terraform apply

[outcatcher]

Done in release v1.19.5
@otc-fabo Please comment if it still reproduces in latest version