Error removing Internal Load Balancer backend (VM-Series) without removing the Load Balancer

[pavelrn]

Describe the bug

If delete a VM-Series instance from Terraform code without deleting the Load Balancer first an error is generated:

local_sensitive_file.init_cfg["fw-vmseries-01"]: Destroying... [id=6e5ef92124063d0b3c82df73f0ca0b9fc75e66a1]
local_sensitive_file.init_cfg["fw-vmseries-01"]: Destruction complete after 0s
local_file.bootstrap_xml["fw-vmseries-01"]: Destroying... [id=c3bc376e73be0af5226c384c3e4401dc931982d8]
local_file.bootstrap_xml["fw-vmseries-01"]: Destruction complete after 0s
module.vmseries["fw-vmseries-01"].google_compute_instance_group.this[0]: Destroying... [id=projects/.../zones/us-east1-b/instanceGroups/example-ipv6-fw-vmseries-01-us-east1-b]
╷
│ Error: Error deleting InstanceGroup: googleapi: Error 400: The instance_group resource 'projects/.../zones/us-east1-b/instanceGroups/example-ipv6-fw-vmseries-01-us-east1-b' is already being used by 'projects/.../regions/us-east1/backendServices/example-ipv6-external-lb-ipv4-ipv6', resourceInUseByAnotherResource
│ 
│ 
╵

Module Version

2.0.7

Terraform version

No response

Expected behavior

VM-Series can be deleted without deleting Internal Load Balancer.

Current behavior

As described above

Anything else to add?

No response